i dont think you can play mpegs streamed on a webiste.. The format has to be WMV or (RP) real player format for streaming video on the web...
Anyways... try updating your video CODECS
first try the micsrosoft video codecs for Media player 9
http://www.microsoft.com/windows/win...cdownload.aspx
and also try these....
kazaa lite codec pack
http://www.k-litecodecpack.com/