Вылезла ошибка на 404 страничке - Joomla 3.x: Общие вопросы

Notice: Undefined index: HTTP_USER_AGENT in /home/c/dgjhg33/public_html/modules/mod_djmegamenu/mod_djmegamenu.php on line 58

$canDefer = preg_match('/(?i)msie [6-9]/',$_SERVER['HTTP_USER_AGENT'])? false : true;

<?php

defined('_JEXEC') or die;

if($this->error->getCode()=='404') {
header('HTTP/1.0 404 Not Found');
	$url=JURI::root()."index.php?option=com_content&view=article&id=187&Itemid=1068";
	$data = file_get_contents($url) or die("Cannot open URL");
    echo $data;
}
?>