Is that realplayer video? I've seen this. It seems to be a conflict between mplayer and realplayer, at least in my case. I guess if you 'Open in stand alone player' you get mplayer, not realplayer?
You could try closing firefox, 'touch'ing the mplayerplug* or nphelix.* files in /usr/lib/mozilla/plugins/ and trying again. This will change which plugins firefox gives priority to (the set with the most recent timestamp iirc). You might find a combination that works better, but if not there's always the standalone player option.
Last edited by henshaw; 27th April 2007 at 03:36 PM.
Reason: forgot path to plugins