Drupal 5: fix comment permalinks with pagination

function mymodule_form_alter($form_id, &$form) {  
  if ($form_id == 'forum_node_form' && $form_id == 'comment_form'){
    $form['#redirect'] = mymodule_comment_redirect($form['nid']['#value']);
  }  
}
 
function mymodule_comment_redirect($nid){
  global $user;
  $uid = $user->uid;
 
  //get the last comment ID
  $sql = "SELECT cid FROM {comments} WHERE nid = %d AND uid = %d ORDER BY timestamp DESC LIMIT 1";
  $cid = db_result(db_query($sql, $nid, $uid));  
 
  //work out totals etc
  $sql2 = "SELECT count(cid) as total FROM {comments} WHERE nid = %d";
  $comment_total = db_result(db_query($sql2, $nid));
  $comment_default_per_page = variable_get('comment_default_per_page', 10);
  $last_page = floor($comment_total/$comment_default_per_page);
 
  //return the redirect url with fragment pager id
  return array('node/'. $nid, "page=".$last_page, "comment-$cid");
}