It is about money. You might get it to go by reducing the video acceleration as noted in the WMP MINI FAQ (hint: type that into google.)

But don't get too upset. DVD playback is a license issue and you pay by video "stream." I'd rather not duplicate the full story, but the short version is that per stream is about 2 bucks. To enable the other output is another 2 bucks for how many that would use it. So they keep the 2 bucks and you end up asking.