I had the exact same problem...

Reading in this forum I founded the solution for me , and I have registered only for reply your message.

do this:

run "/etc/init.d/alsa-autoconfig" as root.

This load your sound modules into the system.

Run Kmix an unset the mute volume for all inputs/outputs.
Try to run Xmms for example, and load a file ... play ... ooooooh! Wanderful!

That's all.. and sorry for my bad english.
Bye from Spain