i do see something else, it seems like the ajax loaded page has code in the head that acts on html that exists on the page. If it is in the head, it will run before the elements that it needs exist. using document.ready isn't an option there since the page you are loading to has already fired the domready event.
Next, the page doesn't appear to have a body tag or a closing html tag. IE is very picky, it needs to be valid html, no extra commas, no unclosed tags, etc.
-- Kevin