Don't call check_plain() on resource variables

On http://localhost/dta/admin/content/taxonomy/1 I get the following error:
warning: preg_match() expects parameter 2 to be string, resource given in /home/chsc/www/drupal6/includes/bootstrap.inc on line 777.

The problem is that the $form array contains a MySQL resource. Adding something like this in drupalforfirebug_array_row_build() solves the problem:

    elseif (is_resource($value)) {
      $output .= "<div>$spacing $color [$key] => resource $colorend </div>";
    }