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Error in installation of Ajax control toolkit

Ameerh24 asked
Last Modified: 2011-10-19
I have downloaded Ajax control toolkit version 1.0618 from codeplex ..
after I had loading AjaxControlToolkit.sln I was trying to view 'SampleWebSite' in browser
but I get the following error ( Note that IIS is already installed into my machine ) :

Server Error in '/SampleWebSite' 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:

Line 30:     <compilation debug="true">
Line 31:       <assemblies>
Line 32:         <add assembly="System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>
Line 33:       </assemblies>
Line 34:     </compilation>

Source File: C:\Inetpub\wwwroot\AjaxControlToolkit(2)\SampleWebSite\web.config    Line: 32

Assembly Load Trace: The following information can be helpful to determine why the assembly 'System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' could not be loaded.

WRN: Assembly binding logging is turned OFF.
To enable assembly bind failure logging, set the registry value [HKLM\Software\Microsoft\Fusion!EnableLog] (DWORD) to 1.
Note: There is some performance penalty associated with assembly bind failure logging.
To turn this feature off, remove the registry value [HKLM\Software\Microsoft\Fusion!EnableLog].


Version Information: Microsoft .NET Framework Version:2.0.50727.832; ASP.NET Version:2.0.50727.832
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Éric MoreauSenior .Net Consultant
Top Expert 2016

have you copied the DLLs into your bin folder or installed the Ajax toolit on your server?


DLLs are already available in Bin folder and Ajax toolkit on my web server


DLL's  : AjaxControlToolkit.dll
and another file : AjaxControlToolkit.pdb


what is System.Web.Extensions ?


any help where to find this System.Web.Extensions.dll plz ?
Senior .Net Consultant
Top Expert 2016
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Hello! I got the same error... However this error pops up during my "installation" of the AjaxControlToolkit - By installation I meant when I was creating a new tab, namely AjaxToolkit, in the Toolbox. I did "choose item" then browsed to the dll, but no tab was created because of the following error message poping up:
1. I believe I have got the correct version of dll for this ajax toolkit from codeflex - it's for visual studio 2005, .net framework 2.0
2. I couldn't find System.Web.Extensions in the GAC [c:\windows\assembly to make a reference. Where else can it be?
Please help me with this installation of ajax control tool kit on Visual Studio 2005. So frustrated. Thanks

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