Function Returning [object]

[addicted]

I am working on a site that uses simple AJAX to browse through RSS feeds, because I am using a API I needed to build some of it uneder the actual script to get it to appear in the right element, my problem is instead of returning the headlines it is returning [object], here is the part that is causing it,

function cb_showheadlines(str) {   //Should Output STR   return str;   }  function hlines(on,id){   thing=agent.call('','showheadlines','cb_showheadlines',id);	document.getElementById(on).innerHTML=thing;}

Here is the page, http://levade.homeip.net/addicted/sirtus/feedtronic2.php