You only have to "run it as Administrator". For example, run a cmd as administrator and execute it directly and I think it shouldl work well, at least for me it does. If you want to run it as a automated task in Windows 2008, you have to mark in the general tab the checkbox with a text similar to "run it with elevated privileges" (I don't know what's exactly the label of the checkbox in the english version of the operating system).
Hope it helps.