XPath over HTML for MSIE

Well...I know the project is on hiatus but I figured I'd give this a shot.

Basically what I'm doing is pulling in an XML file through AJAX and turning it into a document element.

IE is simply refusing to parse it with XPath and I have no idea why - it's working fine in Firefox, and other DOM functions seem to work on the variable I loaded the file into (such as getElementsByTagName).

Does the way your code was implemented make the way I'm using it impossible? I remember something about generated IDs...