Perhaps I'm wrong on this occasion. MSS2 codec - how???? - Ubuntu Forums

MSS2 - Windows Media 9 (vids:MSS2)

MPlayer - The Movie Player

Up to you to decide. Sounds like MPlayer might be the way to go. Else changing the file extension as suggested. But still sounds suspicious. As one poster remarked, it was a DRM scam (maybe only his experience).
MPlayer is very similar to VLC btw.