drupal_add_css() not working...

The title, explains my situation, here is my code (what I am focusing on):

//CSS
drupal_add_css($extjs_path ."/ext-libs/resources/css/ext-all.css");
//Is theme variable set?
if (variable_get(extjs_css,NULL) != NULL) {
  drupal_add_css($extjs_path .'/ext-libs/resources/css/'. variable_get(extjs_css) .'.css');
}

I have also tried:

//CSS
drupal_add_css("/ext-libs/resources/css/ext-all.css");
//Is theme variable set?
if (variable_get(extjs_css,NULL) != NULL) {
  drupal_add_css('/ext-libs/resources/css/'. variable_get(extjs_css) .'.css');
}

drupal_add_js() is working fine.

Here is the complete extjs.module:

// $Id$
/**
 * This module lets users install extjs on their site and configure it through
 * an administration interface. A test block is also provided for testing.
 */
/**
 * implementation of hook_perm()
 */
function extjs_perm() {
  return array('administer Ext JS');
}
/**
 * implementation of hook_help()
 */
function extjs_help($path, $arg) {
  if ($path == 'admin/help#extjs') {
    $txt = 'This module lets users install and configure extjs on their'.
      ' drupal site. Users with \'administer Ext JS\' permissions can'.
      ' configure Ext JS.';
    return '<p>'. t($txt) .'</p>';
  }
}
/**
 * Implementation of hook_menu()
 */
function extjs_menu() {
  $items['admin/settings/extjs'] = array(
    'title' => 'Configure Ext JS',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('extjs_admin_settings'),
    'description' => t('Ext JS Settings'),
    'access arguments' => array('administer Ext JS'),
    'type' => MENU_CALLBACK,
  );
  return $items;
}
//Menu Function
function extjs_admin_settings() {
  $form['extjs_settings'] = array(
    '#type' => 'fieldset',
    '#title' => t('Ext JS Settings'),
    '#description' => t('Settings for the extjs module are in this fieldset')
  );
  $form['extjs_settings']['extjs_css'] = array(
    '#type' => 'textfield',
    '#title' => t('Theme for Ext JS widgets'),
    '#maxlength' => 100,
    '#default_value' => variable_get(extjs_css,NULL),
    '#size' => 70,
    '#description' => t('Name of the css file which contains the theme to use (located in resources/css). Blank = default')
  );
  $form['extjs_settings']['extjs_mode'] = array(
    '#type' => 'radios',
    '#title' => t('Ext JS Mode'),
    '#description' => t('Ext JS mode: Debug (uncompressed libs), Production (compressed libs), or Custom (build to ext.js).'),
    '#default_value' => variable_get(extjs_mode,1),
    '#options' => array(
      t('Debug'),
      t('Production'),
      t('Custom'),
    ),
  );
  $form['extjs_settings']['extjs_adapter'] = array(
    '#type' => 'checkbox',
    '#title' => t('Jquery Adapter'),
    '#description' => t('Check the box to use the jquery adapter.'),
    '#default_value' => variable_get(extjs_adapter,0), 
  );
  return system_settings_form($form);
}

// Add CSS/JS
$extjs_path = drupal_get_path('module','extjs');
//Use Adapter?
if (variable_get(extjs_adapter,0)==1) {
  drupal_add_js($extjs_path ."/ext-libs/adapter/jquery/ext-jquery-adapter.js");
} else {
  drupal_add_js($extjs_path ."/ext-libs/adapter/ext/ext-base.js");
}
//Include correct ext-all:
if (variable_get(extjs_mode,2)==0) {
  drupal_add_js($extjs_path ."/ext-libs/ext-all-debug.js");
} else if (variable_get(extjs_mode,2)==2) {
  drupal_add_js($extjs_path ."/ext-libs/ext.js");
} else {
  drupal_add_js($extjs_path ."/ext-libs/ext-all.js");
}
//CSS
drupal_add_css($extjs_path ."/ext-libs/resources/css/ext-all.css");
//Is theme variable set?
if (variable_get(extjs_css,NULL) != NULL) {
  drupal_add_css($extjs_path .'/ext-libs/resources/css/'. variable_get(extjs_css) .'.css');
}

Can somebody help me figure out what's going on here?

Also, for those who haven't figured it out: I'm trying to implement Ext JS into Drupal 6.