Oh great.. Vista error messages now have even less detail than XP (which would have likely showed the application that caused the issue). You may have to look into Control Panel's event log to see more details on that error (if anything will be useful from there).
In any case, this is highly likely a Video Codec issue -- are you using FFDShow ? if so, what version ? do you remember which codecs you installed on the machine ? and lastly, what WMP version is this ?