I have not gotten VLC to load properly ever. I prefer Mplayer over the rest for video.
I don't think that format is supported by any linux players. I can't find anything on google, google.com/linux, or winamp, that resemble even a glimmer of hope that the format is supported. I toyed with it briefly when I still had Windows on my computer, so I don't know its nuances. Can you play these streams on Windows Media Player or Realplayer? Or, any of the other players out there? If not, it may be only a Winamp thing. perhaps XMMS works with the .nsv format. It does have some compatibilities...