AJAX toolkit "access denied" problem

I am redesigning a site to include AJAX. On a new page that I created that contains a Tab Control, when I copy the page to the site's server, why would I be getting an "access denied" problem for a page that allows anonymous users? When I remove all references and controls for AJAX, it works fine.

Thanks for the information

Some more information on this problem...it seems as if it may be an IIS permission problem. All the AJAX controls run fine on the development machine, but in examining the website even further, any page with interaction, like a textbox with a watermark, I am getting Access Denied errors. Any help on this problem would be appreciated.