kaffeine says audio device busy

[Bram Kuijper]

Hi all,

Suddenly, when I start Kaffeine, it says: "audio output unavailable, 
device is busy()"

when I do
ps ax | grep alsa
or
ps ax | grep xine
not any processes are returned...  how can I restart my sound card, 
without rebooting the whole system.

thanks,
Bram