diff -r 7e0cdf71b1bb -r 917dcc6c4ceb includes/comment.php
--- a/includes/comment.php	Sat Nov 17 22:12:31 2007 -0500
+++ b/includes/comment.php	Sat Nov 17 22:25:37 2007 -0500
@@ -270,6 +270,7 @@
           $real_code = $session->get_captcha($data['captcha_id']);
           if ( $real_code != $data['captcha_code'] )
             $errors[] = 'The confirmation code you entered was incorrect.';
+          $session->kill_captcha();
         }
         
         if ( count($errors) > 0 )