Index: captcha.module
===================================================================
RCS file: /cvs/drupal-contrib/contributions/modules/captcha/captcha.module,v
retrieving revision 1.42.2.37
diff -u -u -p -r1.42.2.37 captcha.module
--- captcha.module	24 Oct 2007 20:15:11 -0000	1.42.2.37
+++ captcha.module	28 Nov 2007 00:26:10 -0000
@@ -235,7 +235,6 @@ function captcha_admin_settings() {
   }
   // field(s) for setting the additional CAPTCHA description
   if (module_exists('locale')) {
-    global $locale;
     $langs = locale_supported_languages();
     $form['captcha_descriptions'] = array(
       '#type' => 'fieldset',
@@ -545,6 +544,12 @@ function captcha_form_alter($form_id, &$
  * Implementation of form #validate.
  */
 function captcha_validate($form_values) {
+  // Check if there is CAPTCHA data available in $_SESSION
+  // If not, the user has most likely disabled cookies
+  if (!isset($_SESSION['captcha'])) {
+    form_set_error('captcha', t('Cookies should be enabled in your browser for CAPTCHA validation.'));
+    return;
+  }
   // Get answer and preprocess if needed
   $captcha_response = $form_values['#post']['captcha_response'];
   $validationdata = $form_values['validationdata']['#value'];