Linkpoint API for Drupal 5

I am in the process of reworking the Linkpoint API for Drupal 5. Im new to drupal and have run into a problem with the module. I keep coming up with Invalid XML. Here is the code:

<?php
// $Id: linkpoint_api.module

define('LINKPOINT_ERROR_SHORT_VIEW', 0);
define('LINKPOINT_ERROR_MEDIUM_VIEW', 1);
define('LINKPOINT_ERROR_LARGE_VIEW', 2);


/********************************************************************
 * Drupal Hooks
 ********************************************************************/

/**
 * Implementation of hook_menu().
 */
function linkpoint_api_menu($may_cache) {

  $items = array();

  if ($may_cache) {
   $items[] = array(
     'path' => 'store/payment/linkpoint_api/form',
     'title' => t('Credit Card Payment'),
	 'callback' => 'drupal_get_form',
	 'callback arguments' => array('linkpoint_api_form'),
     'access' => true,
     'type' => MENU_CALLBACK);
  }
  $items[] = array(
      'path' => 'admin/ecsettings/linkpoint_api',
      'title' => 'Linkpoint API',
      'callback' => 'drupal_get_form',
      'callback arguments' => array('linkpoint_api_ec_settings'),
      'access' => user_access('administer store'),
      'type' => MENU_NORMAL_ITEM,
      'description' => t('Configure Linkpoint API payment gateway'),
    );
  	
  return $items;
}

/**
 * Implementation of hook_help().
 */
function linkpoint_api_help($section = 'admin/help#linkpoint_api') {

  switch ($section) {
    case 'admin/ecsettings/linkpoint_api':
      return t("You need to have a linkpoint merchant account in order to use this module.");

    case 'linkpoint_api/form_submit_guidlines':
      return t("Do not submit this form twice, or you may be double billed!");
  }
}

function linkpoint_api_ec_settings() {

$form = array(
    'linkpoint_api_help' => array(
      '#type' => 'textarea',
      '#title' => t('Explanation or submission guidelines'),
      '#description' => t('This text will be displayed at the top of the credit card submission form.'),
      '#rows' => 5,
      '#required' => TRUE,
      '#default_value' => variable_get('linkpoint_api_help', linkpoint_api_help('linkpoint_api/form_submit_guidlines')),
    ),
    'linkpoint_api_login' => array(
      '#type' => 'textfield',
      '#title' => t('Store ID'),
      '#description' => t("Enter your merchant Store ID."),
      '#required' => TRUE,
      '#maxlength' => 70,
      '#default_value' => variable_get('linkpoint_api_login', ''),
    ),
    'linkpoint_api_ssl_certificate' => array(
      '#type' => 'textfield',
      '#title' => t('SSL Certificate'),
      '#description' => t("Enter your merchant SSL certificate (.pem). It is preferred that you enter full server path (like /home/smb/1234567.pem, not ./1234567.pem) "),
      '#required' => TRUE,
      '#maxlength' => 255,
      '#default_value' => variable_get('linkpoint_api_ssl_certificate', ''),
    ),
    'linkpoint_api_url' => array(
      '#type' => 'textfield',
      '#title' => t('Linkpoint processing URL'),
      '#description' => t('URL of the secure payment processing page, including the port number.'),
      '#required' => TRUE,
      '#maxlength' => 70,
      '#default_value' => variable_get('linkpoint_api_url', 'https://secure.linkpt.net:1129/LSGSXML'),
    ),
    'linkpoint_api_success_url' => array(
      '#type' => 'textfield',
      '#title' => t('Successful payment URL'),
      '#description' => t("This is the destination to which you would like to send your customers when their payment has been successfully completed. The URL must be a Drupal system path (without leading slash), e.g. 'product'. If not set, user will see invoice (recommended)."),
      '#required' => FALSE,
      '#maxlength' => 70,
      '#default_value' => variable_get('linkpoint_api_success_url', ''),
    ),
    'linkpoint_api_debug' => array(
      '#type' => 'radios',
      '#title' => t('Test mode'),
      '#options' => array(t('Disabled'), t('Enabled')),
      '#description' =>  t('If enabled, transactions will be sent in "GOOD" mode - any card numbers will be approved and cards will not be charged. Also, in test mode full connection error description is shown instead of "Sorry - Could not connect to payment gateway."'),
      '#default_value' => variable_get('linkpoint_api_debug', 1),
    ),
    'linkpoint_api_format_not_accepted' => array(
      '#type' => 'radios',
      '#title' => t('How to format error message if card is not accepted'),
      '#options' => array(
        LINKPOINT_ERROR_SHORT_VIEW => t('Simply Accepted, Declined or Duplicate'),
        LINKPOINT_ERROR_MEDIUM_VIEW => t('Linkpoint\'s error message without code (e.g. "The order already exists in the database")'),
        LINKPOINT_ERROR_LARGE_VIEW => t('Full Linkpoint\'s error message (e.g. "SGS-005003: The order already exists in the database.")'),
      ),
      '#default_value' => variable_get('linkpoint_api_format_not_accepted', 0),
    ),
  );

  return system_settings_form($form);
}

/**
 * Implementation of hook_paymentapi().
 */
function linkpoint_api_paymentapi(&$txn, $op) {

  switch ($op) {

    case 'display name':
      return t('Pay with credit card');

    case 'payment page':
      return linkpoint_api_goto($txn);

  }
}

/**
 * Implementation of hook_ec_transactionapi().
 */
function linkpoint_api_ec_transactionapi(&$txn, $op, $a3 = NULL, $a4 = NULL) {
  if ($txn->payment_method != 'linkpoint_api') return NULL;
  
  switch ($op) {
    case 'load':
      $txn->payment = db_fetch_object(db_query("SELECT * FROM {ec_linkpoint_api} WHERE txnid = %d", $txn->txnid));
      break;
    case 'insert':
    case 'update':
      linkpoint_api_save($txn);
      break;
    case 'delete':
      linkpoint_api_delete($txn);
      break;
  }
}


function linkpoint_api_save($txn) {
  if (is_numeric($txn->txnid) && is_numeric($txn->anid)) {

    if (db_result(db_query("SELECT COUNT(txnid) FROM {ec_linkpoint_api} WHERE txnid = '%s'", $txn->txnid))) {
      db_query("UPDATE {ec_linkpoint_api} SET anid = '%s', amount = '%f' WHERE txnid = %d", $txn->anid, $txn->amount, $txn->txnid);
    }
    else {
      db_query("INSERT INTO {ec_linkpoint_api} (txnid, anid, amount) VALUES (%d, '%s', '%f')", $txn->txnid, $txn->anid, $txn->amount);
    }
  }
}

function linkpoint_api_delete($txn) {
  db_query('DELETE FROM {ec_linkpoint_api} WHERE txnid = %d', $txn->txnid);
}

function linkpoint_api_goto($txn) {

  global $base_url;
  $payment_url = str_replace('http://', 'https://', url('store/payment/linkpoint_api/form/'. $txn->txnid, NULL, NULL, TRUE));

  drupal_goto($payment_url);
  exit();
}

/**
 * Controller for collecting and processing credit card data.
 */
function linkpoint_api_page($txnid = null) {

  $output = linkpoint_api_form($txnid);
  print theme('page', $output);

}


/**
 * Build the credit card form.
 */
function linkpoint_api_form($txnid) {
  global $user, $base_url;

  $t = store_transaction_load($txnid);

  // Make sure the user owns the transaction or is an admin.
  if ($user->uid != $t->uid && $user->uid != 1  && !user_access('administer store')) {
    return drupal_access_denied();
  }

  // Make sure the user is connected via SSL
  if (!$_SERVER['HTTPS']) {
    drupal_access_denied();
    return;
  }

  if ($t->items) {
    foreach ($t->items as $p) {
      $product = product_load($p);
      $subtotal += $p->qty * $p->price;
      $items[] = t('%order of <b>%title</b> at %price each', array('%order' => format_plural($p->qty, '1 order', '@count orders'), '%title' => $p->title, '%price' => payment_format($product->price))). "\n";
    }
  }
  
  $form['help'] = array('#value' => t('<div class="help">%linkpoint_api_help</div>', array('%linkpoint_api_help' => variable_get('linkpoint_api_help', linkpoint_api_help('linkpoint_api/form_submit_guidlines')))));

  $form['items'] = array('#value' => theme('item_list', $items, t('Your items')). '</p>');

  // Prepare the values of the form fields.
  $years  = drupal_map_assoc(range(2007, 2021));
  $months = drupal_map_assoc(array('01', '02', '03', '04', '05', '06', '07', '08', '09', '10', '11', '12'));

  $form['expiry_date'] = array(
    '#type' => 'fieldset',
    '#title' => t('Expiration Date'),
  );
  $form['expiry_date']['cc_month'] = array(
    '#type' => 'select',
    '#title' => t('Month'),
    '#default_value' => ($month ? $month : date('m')),
    '#options' => $months,
    '#description' => null,
    '#extra' => 0,
    '#multiple' => false,
    '#required' => true,
  );
  $form['expiry_date']['cc_year'] = array(
    '#type' => 'select',
    '#title' => t('Year'),
    '#default_value' => ($year ? $year : date('Y')),
    '#options' => $years,
    '#description' => null,
    '#extra' => 0,
    '#multiple' => false,
    '#required' => true,
  );

  $form['details'] = array(
    '#type' => 'fieldset',
    '#title' => t('Card details'),
  );

  $form['details']['cc_firstname'] = array(
    '#type' => 'textfield',
    '#title' => t('Cardholder\'s first name'),
    '#default_value' => $t->address['billing']->firstname,
    '#size' => 50,
    '#maxlength' => 50,
  );

  $form['details']['cc_lastname'] = array(
    '#type' => 'textfield',
    '#title' => t('Cardholder\'s last name'),
    '#default_value' => $t->address['billing']->lastname,
    '#size' => 50,
    '#maxlength' => 50,
  );

  $form['details']['cc_number'] = array(
    '#type' => 'textfield',
    '#title' => t('Credit Card Number'),
    '#default_value' => '',
    '#size' => 21,
    '#maxlength' => 21,
    '#description' => null,
    '#attributes' => null,
    '#required' => true,
  );

  $form['details']['cc_ccv'] = array(
    '#type' => 'textfield', 
    '#title' => t('CCV Security Code'),
    '#description' => t('Three digit number on back of card'), 
    '#size' => 3, 
    '#maxlength' => 3, 
    '#required' => true, 
  );

  $form['txnid'] = array(
    '#type' => 'value',
    '#value' => $txnid,
  );

  $form['submit'] = array(
    '#type' => 'submit',
    '#value' => t('Place your order'),
  );

  $form['#method'] = 'POST';
  $form['#action'] = str_replace('http://', 'https://', url("store/payment/linkpoint_api/form/$txnid", NULL, NULL, TRUE));
  return $form;
}

/**
 * Ensure the integrity of the user-submitted data.
 */
function linkpoint_api_form_validate($form_id, $edit) {
  $errors = array();
  if (!$edit['cc_number']) {
    $errors['cc_number'] = t('You must enter a credit card number.');
  }
  elseif (!is_numeric($edit['cc_number'])) {
    $errors['cc_number'] = t('Error in credit card number. Please make sure it is typed correctly.');
  }

  foreach ($errors as $name => $message) {
    form_set_error($name, $message);
  }

  return count($errors) == 0;
}

/**
 * Send the HTTPS POST request and process the returned data.
 */
function linkpoint_api_form_submit($form_id, $form_values) {
  global $user;
  global $base_url;

  $t = store_transaction_load($form_values['txnid']);

//  include_once './includes/dBug.php';
//  new dBug($t);

  //Make sure the user owns the transaction or is admin.
  if ($user->uid != $t->uid && $user->uid != 1) {
    drupal_access_denied();
  }

  //Make sure the user is connected via SSL
  if (!$_SERVER['HTTPS']) {
    drupal_access_denied();
  }

  $d['configfile'] = variable_get('linkpoint_api_login', '');

  $d['result'] = 'LIVE';
  if (variable_get('linkpoint_api_debug', 1)) {
    $d['result'] = 'GOOD';
  }

  $d['cert'] = variable_get('linkpoint_api_ssl_certificate', '');
  
  $xml ="<order>";
  $xml .="<billing>";
  $xml .="<name>" . $t->address['billing']->firstname . " " . $t->address['billing']->lastname ."</name>";
  $xml .="<address1>" . $t->address['billing']->street1 . "</address1>";
  $xml .="<city>" . $t->address['billing']->city . "</city>";
  $xml .="<state>" . $t->address['billing']->state . "</state>";
  $xml .="<zip>" . $t->address['billing']->zip . "</zip>";
  $xml .="<country>" . store_get_country($t->address['billing']->country) . "</country>";
  $xml .="<email>" . $t->mail . "</email>";
  $xml .="</billing>";
  $xml .="<shipping>";
  $xml .="<name>" . $t->address['shipping']->firstname . " " . $t->address['shipping']->lastname ."</name>";
  $xml .="<address1>" . $t->address['shipping']->street1 . "</address1>";
  $xml .="<city>" . $t->address['shipping']->city . "</city>";
  $xml .="<state>" . $t->address['shipping']->state . "</state>";
  $xml .="<zip>" . $t->address['shipping']->zip . "</zip>";
  $xml .="<country>" . store_get_country($t->address['shipping']->country) . "</country>";
  $xml .="</shipping>";
  $xml .="<orderoptions>";
  $xml .="<result>" . $d['result'] . "</result>";
  $xml .="<ordertype>SALE</ordertype>";
  $xml .="</orderoptions>";
  $xml .="<merchantinfo>";
  $xml .="<configfile>" . $d['configfile'] . "</configfile>";
  $xml .="</merchantinfo>";
  $xml .="<creditcard>";
  $xml .="<cardnumber>" . $form_values['details']['cc_number'] . "</cardnumber>";
  $xml .="<cardexpmonth>" . $form_values['exp_date']['cc_month'] . "</cardexpmonth>";
  $xml .="<cardexpyear>" . substr($form_values['exp_date']['cc_year'],2,2) . "</cardexpyear>";
  $xml .="<cvmvalue>" . $form_values['details']['cc_cvv'] . "</cvmvalue>";
  $xml .="<cvmindicator>provided</cvmindicator>";
  $xml .="</creditcard>";
  $xml .="<payment>";
  $xml .="<chargetotal>" . $t->gross . "</chargetotal>";
  $xml .="</payment>";
  $xml .="<transactiondetails>";
  $xml .="<transactionorigin>ECI</transactionorigin>";
  $xml .="<oid>" . $form_values['txnid'] . "</oid>";
  $xml .="<ip>" . $_SERVER['REMOTE_ADDR'] . "</ip>";
  $xml .="</transactiondetails>";
  $xml .="</order>";


// Start CURL session
  $ch = curl_init();

  curl_setopt($ch, CURLOPT_URL, variable_get('linkpoint_api_url', 'https://secure.linkpt.net:1129/LSGSXML'));
  curl_setopt($ch, CURLOPT_POST, 1);
  curl_setopt($ch, CURLOPT_POSTFIELDS, $xml);
  curl_setopt($ch, CURLOPT_SSLCERT, $d['cert']);
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
  curl_setopt($ch, CURLOPT_USERAGENT, "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0)");
  curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE); // this line is used to fix errors on some systems

 $buffer = curl_exec($ch);
  if (curl_errno($ch)) {
    if (variable_get('linkpoint_api_debug', 1)) {
      drupal_set_message(curl_error($ch),'error');
    } else {
      drupal_set_message(t('Sorry - Could not connect to payment gateway.'),'error');
    }
    return str_replace('http://', 'https://', $base_url) . url('../store/payment/linkpoint_api/form/'. $form_values['txnid']);
  } else {
    curl_close($ch);
  }

  preg_match_all ("/<(.*?)>(.*?)\</", $buffer, $outarr, PREG_SET_ORDER);

  $n = 0;
  while (isset($outarr[$n])) {
    $retarr[$outarr[$n][1]] = strip_tags($outarr[$n][0]);
    $n++;
  }

  switch ($retarr['r_approved']) {

    case "APPROVED": // Credit card successfully charged
      if ((!$retarr['r_ordernum']) && (!variable_get('linkpoint_api_debug', 1))) {
        drupal_set_message(t('No ordernumber received from Linkpoint'),'error');
      }
      $t->anid      = $retarr['r_ordernum'];
      $t->amount    = $t->gross;
      $t->payment_status = payment_get_status_id('completed');
      $t->payment_method = 'linkpoint_api';

      unset($form_values['details']['cc_number']); // will prevent from saving cc_number in the case if some module will save entire transaction data

      $is_new = (db_result(db_query('SELECT COUNT(txnid) FROM {ec_linkpoint_api} WHERE txnid = %d', $form_values['txnid']))) ? false : true;

      $txnid = store_transaction_save((array)$t);

      if ($is_new && $txnid) {
        // Compose and send confirmation email to the user
        store_send_invoice_email($txnid);
      }

      drupal_set_message("Thank you ! Your credit card has been accepted. You will receive confirmation by email shortly.");
      $url=trim(variable_get('linkpoint_api_success_url', ''));
      if ($url) {
        // We want to go to a http, not https.
        return str_replace('https://', 'http://', $base_url). '/' . $url;
      } else {
        return str_replace('https://', 'http://', $base_url). '/store/transaction/view/' . $form_values['txnid'];
      }
      break;

    default: // Credit card error: card was not charged.

      switch (variable_get('linkpoint_api_format_not_accepted',0)) {
        case 0:
          $error=$retarr['r_approved'];
          break;
        case 1:
          $error=preg_replace('/^(.*?: )/','',$retarr['r_error']);
          break;
        case 2:
          $error=$retarr['r_error'];
          break;
      }
      drupal_set_message(t('Your card was not billed for the following reason:<br><strong>%linkpoint_api_error</strong>', array('%linkpoint_api_error' => t($error))), 'error');
      return str_replace('http://', 'https://', $base_url) . url('../store/payment/linkpoint_api/form/'. $form_values['txnid']);
      break;
  }
}

If anyone can help, it would be appreciated.