[jQuery] ajaxForm doesnt work in Internet Explorer

Hi. We have added ajax to our forms by using iframe and it works fine in Firefox. However in Internet Explorer it does not.
Can anyone spot why it doesnt work?
<a href="http://pastebin.com/fe04a2f3">http://pastebin.com/fe04a2f3</a>
We are using JQuery 1.2.6