Session logs out when game is started

[Atega]

Hi, I'm quite a newbie to Nexiuz, but the problem that i'm having is:
when I start the game from either nexuiz-linux-glx.sh or nexuiz-linux-sdl.sh in my /home/ directory, the screen goes black, then the current session is either running in the background or has been closed, and i'm returned to the login prompt. When i login again, there is no sign of the game having started or otherwise.

Why is this happening and how can i get the game to run properly?

Specs:
Fedora Core 8 (Kernel 2.6.23.1-42-fc8)
2Gb Mem
2GHz/core Intel Core 2 Duo Processor
512Mb Video Memory
NVIDIA 7600 GPU

Thanks!