Firefox no audio on fedora while streaming video

My apology if i'm not on the right forum to post.

Hope anybody out there could help me out with this problem.

i'm running firefox 3.5 on fedora, then streaming video from websites like youtube produces no audio. i have flash-plugin from adobe installed on the system

here is the what i have noticed earlier:

ALSA lib pcm_pulse.c:724:(pulse_prepare) PulseAudio: Unable to create stream: Invalid argument

Audio works fine when i play music locally using mplayer.

Other users like you have reported the same for Fedora, as it seems. One of them suggests that upgrading to the last alsa version fixes his problem ... I had the same issue when I was running Fedora 8, and this was one of the reasons to switch the distro, but that's another story.