Quote Originally Posted by si_the_geek View Post
Ajax doesn't necessarily mean AjaxControlToolkit.

I would recommend making sure that AjaxControlToolkit is installed on the server, but I'm afraid I haven't used it myself so don't know the steps to do that.
For the toolkit, all I believe you need to do is drop the AjaxControlToolkit.dll in the /bin/ folder, which I have done. I literally took the code from one host and copied it to 1&1. I've never had this issue and I've been using this toolkit for years.