Here's what I have tried sofar:

I've added some code to stop, clear and unload the movieclip with the flv-file.

on (release){
_root.mp3player.gotoAndPlay("quiet");
_root.container.container_video.clip1.stop();
_root.container.container_video.clip1.clear();
_root.container.container_video.unloadMovie();
_root.container.container_video.loadMovie("video/nameofmovieclip.swf", "container_video");
}

I have tried uninstalling the Flash player and reinstalling it again.

The number of clips I can watch differs between different computers. I would suspect it is some kind of memory / buffer / overflow bug.

Can anyone else confirm that they have problems watching the clips in the link at the top?