I downloaded and installed the latest emu10k1 driver (as of 11/28/02, version 0.20a), and was able to get sound working correctly, but only when logged in as root. Running X 4.2.0 with GNOME 2.0 as any user besides root resulted in an error saying that GNOME wasn't able to open /dev/mixer. GNOME also suggested that I check to be sure I had permission to access /dev/mixer. Since I'm not sure if there's a better way to do this, I went ahead and ran chmod 777 /dev/mixer. Now, GNOME doesn't throw an error, but I still have no sound. Any ideas how this can be corrected?

Try ls -l /dev/mixer and ls -l /dev/dsp
If the devices are in the group "audio" for example, you have to put also the system user in the group with the command: adduser [user] audio

Greetings