WRN: Assembly binding logging is turned OFF. To enable assembly bind failure logging, set the registry value [HKLM\Software\Microsoft\Fusion!EnableLog]

Se você recebeu o ERRO:

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:

Line 37:
Line 38:
Line 39:
Line 40:
Line 41:

Source File: C:\Inetpub\vhosts\littleoak.com.br\httpdocs\web.config Line: 39

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].

NADA de pânico, você só precisa acessar o site da Microsoft, instalar o Asp.Net ajax e ser feliz:

http://www.microsoft.com/downloads/details.aspx?FamilyID=ca9d90fa-e8c9-42e3-aa19-08e2c027f5d6&displaylang=en

Após download instale o aplicativo em na máquina aonde o erro ocorreu (servidor) e seja feliz com o asp.net ajax.