when you try to deply AJAX ASP.Net application make sure ofthe following :
1) on IIS,the web site select asp.net 2.0.
2) on IIS,Make sure the Execute Permssion under Home Directory tab is Scripts Only.
3) AJAX Runtime should be installed on the production since it doesn't contains the extedability dlls used by ajax such as System.Web.Extensions.dll.
see the below error if you didnt install the AJAX Runtime on the production.