I tried running the official viewer in 64-bit Linux (OpenSUSE 11.1) and could not hear any music. I could hear ambient sounds, so the basics are there. It's just music that's missing.
I checked my preferences and they're correct. The viewer is picking up the fact that there's a music stream, so that's not the problem. I've looked and looked, but it doesn't seem to be a chair-keyboard interface problem.
Curiously, I can get music from the Cool viewer, but not the Emerald one. So what does the Cool viewer do that the official viewer and the Emerald viewer don't? (Confine your answers to this problem please!)