Index: comment.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/comment.module,v
retrieving revision 1.459
diff -u -p -r1.459 comment.module
--- comment.module	20 May 2006 08:14:09 -0000	1.459
+++ comment.module	23 Jun 2006 08:33:19 -0000
@@ -1102,16 +1102,27 @@ function comment_multiple_delete_confirm
 
   $form['comments'] = array('#prefix' => '<ul>', '#suffix' => '</ul>', '#tree' => TRUE);
   // array_filter() returns only elements with actual values
+  $comment_counter = 0;
   foreach (array_filter($edit['comments']) as $cid => $value) {
-    $subject = db_result(db_query('SELECT subject FROM {comments} WHERE cid = %d', $cid));
-    $form['comments'][$cid] = array('#type' => 'hidden', '#value' => $cid, '#prefix' => '<li>', '#suffix' => check_plain($subject) .'</li>');
+    $comment = _comment_load($cid);
+    if (is_object($comment) && isset($comment->cid) && ctype_digit($comment->cid)) {
+      $subject = db_result(db_query('SELECT subject FROM {comments} WHERE cid = %d', $cid));
+      $form['comments'][$cid] = array('#type' => 'hidden', '#value' => $cid, '#prefix' => '<li>', '#suffix' => check_plain($subject) .'</li>');
+      $comment_counter++;
+    }
   }
   $form['operation'] = array('#type' => 'hidden', '#value' => 'delete');
-
-  return confirm_form('comment_multiple_delete_confirm', $form,
-                      t('Are you sure you want to delete these comments and all their children?'),
-                      'admin/comment', t('This action cannot be undone.'),
-                      t('Delete comments'), t('Cancel'));
+  
+  if (!$comment_counter) {
+    drupal_set_message(t('There do not appear to be any comments to delete or your selected comment was deleted by another administrator'));
+    drupal_goto('admin/comment');
+  }
+  else {
+    return confirm_form('comment_multiple_delete_confirm', $form,
+                        t('Are you sure you want to delete these comments and all their children?'),
+                        'admin/comment', t('This action cannot be undone.'),
+                        t('Delete comments'), t('Cancel'));
+  }
 }
 
 /**
@@ -1646,6 +1657,12 @@ function theme_comment_post_forbidden($n
 }
 
 function _comment_delete_thread($comment) {
+  
+  if (!is_object($comment) || !isset($comment->cid) || !ctype_digit($comment->cid)) {
+    watchdog('content', t('Warning, cannot deleted non existent comment'), WATCHDOG_WARNING);
+    return;
+  }
+  
   // Delete the comment:
   db_query('DELETE FROM {comments} WHERE cid = %d', $comment->cid);
   watchdog('content', t('Comment: deleted %subject.', array('%subject' => theme('placeholder', $comment->subject))));