How are you trying to enable sound?
Also, what kind of soundcard do you have? Have you gotten the module installed okay?
If you open up a terminal and type:
ls -l /dev/dsp
What do you get? Hopefully you get something. If you do, then you should probably chmod 755 /dev/dsp and also chmod 755 /dev/mixer so users can have sound in X. Let me know.
