video/x-asf-unknown or MSS2 are two codecs required to play windows media files. If you’re unable to play them on your using regular media players on your Ubuntu, install Mplayer and you should be good to play any WMA files.
If you have already installed Mplayer and still have issues playing wma files, then download the codes from Mplayer website and copy them to /usr/lib/win32 and then start Mplayer.




