I'm doing some experimenting and found that a simple sequential play of a small sound file caused an assertion in the pulse audio plugin. The base system is Fedora 8, and it uses alsa 1.0.16 versions. I looked at the 1.0.19 versions and they still have assertions, so the problem may still be there. It is pretty easy to trip up:
$ aplay blah.wav blah.wav Playing WAVE 'blah.wav' : Signed 16 bit Little Endian, Rate 44100 Hz, Stereo Playing WAVE 'blah.wav' : Signed 16 bit Little Endian, Rate 44100 Hz, Stereo aplay: pcm_pulse.c:524: pulse_hw_params: Assertion `!pcm->stream' failed. Aborted by signal Aborted...
(where "blah.wav" is a simple short wav file) The first time through, it plays find, but the second time it doesn't.
If this has been solved in 1.0.19, (I haven't installed it), please let me know and I'll go away. If not, it may be a problem in the pulse audio thing.
Thanks.