I'm using C# and was trying to incorporate AJAX Controls but I keep getting this error.

Could not load file or assembly 'AjaxControlToolkit' or one of its dependencies. The system cannot find the file specified.

Source Error:

<%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="cc2" %>

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].

How do I resolve this issue?

Thanks