Please forget the 'fix'. I've tested a little bit more and it's not this line but the used alsa device that is responsible for the problems.
If I use device
hw:0,0 I get no error and the sound is fine, with
dmixer I get no error, but the sound is ugly and finally with
default I get the both error message and ugly sound.
- hw:0,0 is the plain pcm device
- dmixer is the playback part of the same pcm device with the dmix plugin configured
- default maps to the asym plugin with dmix and dsnoop configured
I've checked the other two sound implementations, oss and sdl, too, but they didn't work either
With oss I get big gaps between two played samples (the gaps depend on the used sample rate), like tok.........tok.........
And sdl (uses alsa, too) doesn't play any sounds.
With both variants I get no error messages.