// (c) Copyright Microsoft Corporation.
// This source is subject to the Microsoft Public License.
// See http://www.microsoft.com/opensource/licenses.mspx#Ms-PL.
// All other rights reserved.

You must go to 
for .net 3.5: http://ajaxcontroltoolkit.codeplex.com/releases/view/65800#DownloadId=236793 
for .net 4.0: http://ajaxcontroltoolkit.codeplex.com/releases/view/65800#DownloadId=236792
and download ajaxcontroltoolkit 
then Copy AjaxControlToolKit Like Picture in demo file
and paste them to Bin Folder  

Right Click on solution choose Add Reference 
in the browse tab double click on the Bin Folder, 
and double click on ajaxcontroltoolkit.dll 
then on the Build Menue > click Rebuild Website.
If you have any questions please do not hesitate to contact info@mahsakashi.com OR kashi_mahsa@yahoo.com





