When installing the windows 7 sdk on my dev server that is running the windows server 2008 r2 OS, the installation procedure was aborted because the SDK could only be installed on a windows 7 machine.

There is a workaround, but it is not supported

http://blogs.msdn.com/b/astebner/archive/2010/05/02/10005980.aspx

Hope it helps,

Tom