New Patch is HERE (August 30th!!) Feedback needed for final release.

[DeM]

I found this in the ubuntu forums:

-Edit or create the file: "~/.pulse/client.conf" so it says "autospawn = no"
-The kill pulseaudio by typing "killall pulseaudio" in the Terminal.
-Play Penumbra, hopefully with perfect audio!
-Type "pulseaudio -D" in the Terminal when done playing.

Yes, it worked for me. I've applied that solution and I've sucesfully played the three games without sound glitches in Ubuntu 9.10 64bits.

Thanks Jens. And thanks for making games in linux.