MMDEVAPI is part of the audio stack in Vista - the acronym stands for MultiMedia DEVice API - but I don't understand why you'd get a window with this title. It's quite common for trojans to masquerade as legitimate applications so perhaps you have something nasty on your machine. Or, it could just simply be that you have something wrong with your machine.

http://blogs.msdn.com/larryosterman/...23/473351.aspx