[CentOS] firefox and mplayer failures

Does anyone else have problems with playing video/audio files under
firefox with mplayer? Almost everything I try (the latest were some
.asf and .wmv clips) craps out under firefox, but if I save to disk
and play with mplayer, they work just fine.

CentOS 4.1 with latest updates and the following related to the problem.

mplayer-fonts-1.1-3.0.rf
mplayerplug-in-3.11-1.2.el4.rf
mplayer-1.0-0.17.pre7.2.el4.rf
firefox-1.0.6-1.4.2.centos4

--
Collins Richey
      Debugging is twice as hard as writing the code ... If you write
      the code as cleverly as possible, you are, by definition, not
      smart enough to debug it.
             -Brian Kernighan