When I was trying to add Ajax AutoComplete using Ajax Toolkit in VS 2008, I got an error. Please see the description below.

Question

I'm having an error here : Please go through this and tell me what's the error. Server Error in '/WebSite1' Application.

Could not load type 'System.Web.UI.ScriptReferenceBase' from assembly 'System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'.
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.TypeLoadException: Could not load type 'System.Web.UI.ScriptReferenceBase' from assembly 'System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'.

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:

[TypeLoadException: Could not load type 'System.Web.UI.ScriptReferenceBase' from assembly 'System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'.]
   AjaxControlToolkit.ToolkitScriptManager.OnResolveScriptReference(ScriptReferenceEventArgs e) in d:\hg\act\Server\AjaxControlToolkit\ToolkitScriptManager\ToolkitScriptManager.cs:276
   System.Web.UI.ScriptManager.RegisterScripts() +261
   System.Web.UI.ScriptManager.OnPagePreRenderComplete(Object sender, EventArgs e) +117
   System.Web.UI.Page.OnPreRenderComplete(EventArgs e) +2063008
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +2247


Version Information: Microsoft .NET Framework Version:2.0.50727.1433; ASP.NET Version:2.0.50727.14

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Answer 1

Make sure correct version of .net framework(.net 3.5 SP1) is installed on server.Also try to replace ajaxToolkit:ToolkitScriptManager to asp:ScriptManager in the aspx file