AHAH 403 error on the AHAH path

Hello.

I'm trying to create an AHAH example solution for a form and I've run into a problem where I'm getting a 403 error from the AHAH callback.

Here is the specific error: An HTTP error 403 occurred. /my_module/js

And this is the code:

/**
 *  Implementation of hook_menu. Adds a page callback for the form
 *  and a menu callback for the AHAH button to work on.
 *
 **/
function my_module_menu() {
  $items = array();

  $items['admin/ahah/ahah_test'] = array(
    'title' => 'AHAH test',
    'description' => 'This is an AHAH test.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('my_module_ahah_form'),
    'access arguments' => array('access content'),
  );
  
  $items['my_module/js'] = array(
    'title' => 'AHAH Test callback',
    'page_callback' => 'my_module_js',
    'access arguments' => array('access content'),
    'type' => MENU_CALLBACK,
  );

  return $items;
}

/**
 *  Callback for the AHAH magic, defined in hook_menu as a path
 *  and added to the form on submit buttons AHAH property.
 *
 *  The return HTML will be output by AHAH, needs to be JSON formatted.
 *
 **/
function my_module_js() {
  return drupal_json(array('status' => TRUE, 'data' => "Hello Drupal World"));;
}

/**
 *  The actual form, defines a fieldset and a wrapper containing a field and
 *  a button that calls the AHAH page that is defined in hook_menu.
 *
 **/
function my_module_ahah_form() {
  $form = array();
  
  // A div wrapper for everything
  $form['wrapper'] = array(
    '#prefix' => '<div id="my-wrapper">',
    '#suffix' => '</div>',
  );
  
  // A div wrapper for the JS to work on which will contain the fields
  $form['wrapper']['fields'] = array(
    '#prefix' => '<div id="more-fields">',
    '#suffix' => '</div>',
  );
  
  // A field into the fields-wrapper for form input
  $form['wrapper']['fields']['text_1'] = array(
    '#type' => 'textfield', 
    '#title' => t('Textfield'),
  );
  
  // A button with special AHAH properties and a special submit
  $form['wrapper']['add_fields'] = array(
    '#type' => 'submit',
    '#value' => t('Add text'),
    '#description' => t("If the amount of fields above isn't enough, click here to add more fields."),
    '#submit' => array('my_module_more_fields_submit'), // If no javascript action, use this.
    '#ahah' => array(
      'event' => 'click',         // Other options, change/blur
      'path' => 'my_module/js',   // Path defined in hook_menu
      'wrapper' => 'more-fields', // The wrapper for the AHAH content
      'method' => 'after',      // Replaces current content in the wrapper, options are: after/append/before/prepend
      'effect' => 'fade',         // The effect, could also be none/slide
      'progress' => array(
        'type' => 'bar',          // Progress type is bar
        'message' => t('Loading...'),
      ) 
    )
  );
  
  return $form;
}

I'd be very grateful for any input on this.

span