After deploying the code to production server, I got the below mentioned error on login. We have recently upgraded the Telerik version to the latest 2012.3.1308.35 product version.

As per the below error, a method is missing from System.Web.UI but we can see that method in the Object Browser. Please provide some suggestions to resolve this issue.

Method not found: 'System.Web.UI.CompositeScriptReference System.Web.UI.ScriptManager.get_CompositeScript()'.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.MissingMethodException: Method not found: 'System.Web.UI.CompositeScriptReference System.Web.UI.ScriptManager.get_CompositeScript()'.
Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:

 [MissingMethodException: Method not found: 'System.Web.UI.CompositeScriptReference System.Web.UI.ScriptManager.get_CompositeScript()'.]   Telerik.Web.UI.RadScriptManager.OnResolveScriptReference(ScriptReferenceEventArgs e) +0   System.Web.UI.ScriptManager.RegisterScripts() +261   System.Web.UI.ScriptManager.OnPagePreRenderComplete(Object sender, EventArgs e) +117   System.EventHandler.Invoke(Object sender, EventArgs e) +0   System.Web.UI.Page.OnPreRenderComplete(EventArgs e) +2060736   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1566

Version Information: Microsoft .NET Framework Version:2.0.50727.1891; ASP.NET Version:2.0.50727.1887