Created Unassigned: Error trust level="Full" [27690]

I am new to ASP.NET and started using Ajax. I have downloaded AjaxControllToolkit3.5 and registered on my system. Some day it work proper. After some days suddenly I have opened It's Sample site in Visual studio 2008, I got Error as under.

"
Server Error in '/AjaxControlToolkit.Binary.NET35' Application.
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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: It is an error to use a section registered as allowDefinition='MachineToApplication' beyond application level. This error can be caused by a virtual directory not being configured as an application in IIS.

Source Error:


Line 59:
Line 60: <httpRuntime executionTimeout="90" maxRequestLength="2097151" />
Line 61: <trust level="Full" />
Line 62:
Line 63: <sanitizer defaultProvider="HtmlAgilityPackSanitizerProvider">


Source File: E:\Learning DOT NET C#\AjaxControlToolkit.Binary.NET35\ajaxcontroltoolkitsamplesite\web.config Line: 61



Show Additional Configuration Errors:


It is an error to use a section registered as allowDefinition='MachineToApplication' beyond application level. This error can be caused by a virtual directory not being configured as an application in IIS. (E:\Learning DOT NET C#\AjaxControlToolkit.Binary.NET35\ajaxcontroltoolkitsamplesite\web.config line 95)
It is an error to use a section registered as allowDefinition='MachineToApplication' beyond application level. This error can be caused by a virtual directory not being configured as an application in IIS. (E:\Learning DOT NET C#\AjaxControlToolkit.Binary.NET35\ajaxcontroltoolkitsamplesite\web.config line 138)
"

Can any body help me about this error and how to update Web Config.
Thanks !