Thanks for the hint!
I "killed" one of the createSample methods in SoundManager (where the crash occurs):
public int createSample(String url, int soundNode, int event)
{
return -1;
}
After this the game runs, and the sound seems fine (At least I missed nothing, so I probably killed just less important ones).
BTW: Cool game. I wished there would be further development, but I'm still a noob regarding JME…
The website seems to be down (
Guys, this thread is 4 years old…