Same here. Only get Segment fault all the time.
Tried surgestions above same result.

I run 64bit version of PlaneShift for Linux

If I run ./psclient directly I get:
crystalspace.pluginmgr.loadplugin:
  could not load plugin 'crystalspace.sndsys.renderer.null'
shader lighting_character: shader particles_soft-alpha: ....10%....20%....30%....40%....50%....60%....70%....80%....90%....100%
....10%....20%....30%....40%....50%....60%....70%....80%....90%....100%
Segmenteringsfel

My System is:
CPU: Intel Core i7 920
RAM: 6GB DDR3 1.6GHz
Graphics Card: Nvidia 8600GT 512MB Silent
OS: Ubuntu 9.10 64bit
Graphics driver: Ubuntu Restricted drivers recomended; nvidia 185

Iv tride various combinations of graphical settings for the game without success.
I play both other native Linux 3D games aswell as graphical heavy Windows games through Wine and CrossOver Games without major issues.