[Plugin: IntenseDebate XML Importer (Blogger to WordPress)] Plug in not reading the XML code

I followed the directions to the T and when I go to upload my XML file into your plugin, it says that it’s not a valid XML code. I exported the code from IntenseDebate, and downloaded the file. Not understanding why it’s saying it’s not valid. Please help! I want my comments back!!

http://wordpress.org/extend/plugins/intensedebate-xml-importer-blogger-to-wordpress/