I installed Debian 4.0r3 on my workstation. Since any months I use amarok as my favorite music player and it worked great on several distributions.
But not on my Debian system. After some seconds of a playing track the following message pops up:

xine was unable to initialize any audio drivers.

So when I pressed the OK button, the message went away and amarok freezed at the same time.

After investigating some times for finding a solution, I got one that helped me.
I just had to disable the crossfading.

I guess it's a bug in the amarok version (my version is 1.4.4).

Source:
http://amarok.kde.org/forum/index.php/topic,2084.0.html