error Could not load type "System.Web.UI.IScriptManager"

Hi, All,

please find the error that i am finding below. i have an application that is
using the ajax asp.net controls like updatepanel. I have visual studio 2005
installed on my developer machine. On the developer end this page is working
perfectly but on the server end when i am uploading this in not working and
it is giving the error below. can anyone please help me out.

thanking you
Shake