diff --git modules/comment/comment.module modules/comment/comment.module
index 31e37be..0e7edb5 100644
--- modules/comment/comment.module
+++ modules/comment/comment.module
@@ -2062,7 +2062,6 @@ function comment_preview($comment) {
   $node = node_load($comment->nid);
 
   if (!form_get_errors()) {
-    $comment->format = $comment->comment_body[LANGUAGE_NONE][0]['format'];
     // Attach the user and time information.
     if (!empty($comment->name)) {
       $account = user_load_by_name($comment->name);
@@ -2180,6 +2179,9 @@ function comment_submit($comment) {
     // 1) Filter it into HTML
     // 2) Strip out all HTML tags
     // 3) Convert entities back to plain-text.
+    if(!isset($comment->comment_body[LANGUAGE_NONE][0]['format'])){
+      $comment->comment_body[LANGUAGE_NONE][0]['format'] = 'NULL';
+    }
     $comment->subject = truncate_utf8(trim(decode_entities(strip_tags(check_markup($comment->comment_body[LANGUAGE_NONE][0]['value'], $comment->comment_body[LANGUAGE_NONE][0]['format'])))), 29, TRUE);
     // Edge cases where the comment body is populated only by HTML tags will
     // require a default subject.