Ajax client-side framework failed to load - issue!!!

I recently found this problem when trying to get url rewritten pages to work without an extension.  what i needed to do was to make sure the .axd mapping was in place - which it was in my case.  then i needed to make sure that verify exists is unticked. After that i had no more issues with this.  hope this helps someone else out there.  again this is specific to a windows 2003 server so the solution may vary for other servers