Could not load file or assembly System.Web.Extensions

Introduction

Facing issue when my team member try to upload compiled source code from her development machine to new production server.The error is like following

Server Error in '/' Application.

Configuration Error

Description: An error occurred during the processing of a configuration file required to service this request. Please review the specific error details below and modify your configuration file appropriately.

Parser Error Message: Could not load file or assembly 'System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified.

Source Error:
 

</httphandlers>
<httpmodules>
<add type="System.Web.Handlers.ScriptModule, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" name="ScriptModule">
</httpmodules>
</SYSTEM.WEB>

Solutions

1. Copy AjaxControlToolkit.dll and AjaxControlToolkit.pdb version 1.0.61025.0 from my development machine to my ASP.NET App bin folder. (i install my AjaxControlToolkit in C:\Program Files\Microsoft ASP.NET\ASP.NET 2.0 AJAX Extensions\AjaxControlToolkit)
2. Copy System.Web.Extensions.dll (C:\WINDOWS\assembly\GAC_MSIL\System.Web.Extensions) and System.Web.Extensions.Design.dll (C:\WINDOWS\assembly\GAC_MSIL\System.Web.Extensions.Design) from my development machine to my ASP.NET App bin folder.

Note:I have assume you also installed C drive, if not please check assembly location according your location.

The problem solved.hope this is save your time.