XML : How to use smarty?

I am using Pligg CMS for one of my websites and I am trying to parse and display an xml file using smarty. So here is the code that i have used to do that

  {$xml = simplexml_load_file('http://localhost/pligg/featured.xml')}    {if !empty($xml)}    {$cnt = 0}    {foreach $xml->container->item as $item}      <h4><a href="{$item->link}">{$item->title}</a></h4>      <h2>{$item->image}</h2>    {/foreach}  {else}    <p>No feed found...</p>  {/if}    

but when i use this code in my homepage, the page goes completely blank and doesnot written anything. So what am i doing wrong?