Demo crashes - audio problem [ubuntu]

[zk123]

When I try to play the
Amnesia demo, it first starts normally, tells me the normal stuff, asks
for gamma setting (which all look the same to me, btw), I get to the first
loading screen and then it's just gone.


The terminal output is at http://paste.ubuntu.com/952375/, seems to be some kind of audio problem.
The sound in the menu works fine.