If you have sound with other applications, it could be that you’re using oss which lets only one application at a time use the audio device. Eiither that or you’re using pulseaudio which has potential, but is still buggier than a volkswagen. Run alsaconf to reconfigure your sound card with alsa.
Well, I’m using pulseaudio. But if I run Sauerbraten with sudo, I get sound to work. Maybe it’s a permission problem, I just didn’t figure it out which permission it is.