Comment 6 for bug 151849

The sound is definitely working for other programs (sorry, should have stated that for sure).
I went through and installed the newest version of Flash as per the instructions in the thread you linked to above, Cyrus.
There is no .asoundrc file in my home directory (or in anyone else's).
There are no messages (error or otherwise) when I start Firefox from the command line.
I'm using Ubuntu release 7.10; 2.6.22-14-generic kernel.
(Also, may be helpful to note that it's not just a problem with Youtube. I also get no sound from Pandora Radio, which is also flash based.)

Anything else that I could try/give information on?