It should run under Vista without any problem ..
Maybe try to run Beoplayer in XP compatible mode
(right mouse key on the beoplayer tab in start menu, go to properties and then select compatibility)
did you install all patches for Vista ? If it is an official release, then you can update via explorer.
Of course it is a Microsoft OS ... So you need to reinstall from time to time to get it stable again. I'm using beoplayer also in Vista SP2 but with VMWare on MAC osX and this runs fine
nico