If you're trying to use a ColdFusion AJAX-related tag, such as <cffileupload>, you will notice that your HTML source now includes references to JavaScript files, located in /CFIDE/scripts/…
But, under a typical multi-site configuration, using VirtualHosts, this path is not accessible at the root of the website.
The quickest thing to do is to create a symbolic link at the root of your site, i.e.
ln -s /path/to/cfide CFIDE