The request filtering module is configured to deny the file extension for .ascx file

Hello All ,
On IIS 7.0 and above with only IE 10 i came across an issue "The request filtering module is configured to deny the file extension" 
the requst is blocked since the extension is of type .ascx hence
i have set to Allow the .ascx extension in the applicationHost config file found on the path %WinDir%system32/inetsrv/config/

                    <add fileExtension=".ascx" allowed="True" />

but then i get the error"The page you are requesting cannot be served because of the extension configuration. If the page is a script, add a handler. If the file should be downloaded, add a MIME map" and stops me from processing further.

Please help me it's Urgent