while i am installing windows phone 7 SDK following error is occured and setup can not complete.

Any one know how to resolve this error and install Windows Phone 7 SDK.
i already installed Microsoft Visual Studio 2010 Ultimate but still installation error is coming
Thanks In Advance.
But have you installed SP1? If not, go ahead and install this:
http://www.microsoft.com/en-us/download/details.aspx?id=23691