Error at removal node with comments

I ask a pardon for bad English. At removal node with comments there is an error.

The decision:

hidden_comment.module

To replace:

function hidden_comment_comment_delete($comment) {
  db_delete('comments_hide')
  ->condition('cid', $a1->cid)
  ->execute();
}

on:

function hidden_comment_comment_delete($comment) {
  db_delete('comment_hide')
  ->condition('cid', $comment->cid)
  ->execute();
}

Pay attention: comments_hide (error), $a1->cid (error).

***

Besides, a suspicious fragment:

hidden_comment.views.inc

function hidden_comment_views_data() {
$data['comments_hide'] = array(

P.S. Thanks for the excellent module!