NetStream problem on some browsers

[mutant]

I am using a videoObject and streams a flv file with NetStream like this ::

var connection:NetConnection;
var stream:NetStream;
var audio_sound:Sound;

connection = new NetConnection();
connection.connect(null);
stream = new NetStream(connection);
video_object.attachVideo(stream);
stream.play('flashvideo.flv');
audioContainer.attachAudio(stream);
audio_sound = new Sound(audioContainer);

This is working great in IE on both Mac and PC, but fails showing anything on Firefox ( PC ) and Safari ( Mac ), but I am able to read the

audio_sound.getVolume()

Anybody knows why ?

Stian Johansen