Nexuiz restarts PC what can I do?

[asadujjaman]

I have downloaded nexuiz-23.zip from sourceforge. The included .exe runs fine under windows but whenever I try to run the nexuiz-linux-sdl.sh under linux, the system restarts. Then I did the same thing nexuiz-linux-sdl.sh>details.txt and the system again restarted. The contents of details.txt is posted here. Please help if it means anything...

[Contents of details.txt]
Console initialized.
Nexuiz Linux 16:37:54 May 30 2007
Trying to load library... "libz.so.1" - loaded.
Compressed files support enabled
Added packfile data/common-spog.pk3 (26 files)
Added packfile data/data20070531.pk3 (3675 files)
Trying to load library... "libcurl.so.4" - loaded.
cURL support enabled
Initializing client
Failed to init SDL joystick subsystem:
Trying to load library... "libvorbis.so.0" - loaded.
Trying to load library... "libvorbisfile.so.3" - loaded.
Ogg Vorbis support enabled
couldn't exec config.cfg
couldn't exec data/campaign.cfg
couldn't exec autoexec.cfg
Starting video system
Video: fullscreen 800x600x32x60hz
Linked against SDL version 1.2.11
Using SDL library version 1.2.11
Failed to set video mode to 800x600: Couldn't find matching GLX visual
Desired video mode fail, trying fallbacks...
Video: fullscreen 800x600x32x60hz
Linked against SDL version 1.2.11
Using SDL library version 1.2.11
Failed to set video mode to 800x600: Couldn't find matching GLX visual
Video: fullscreen 800x600x16x60hz
Linked against SDL version 1.2.11
Using SDL library version 1.2.11
[/Contents of details.txt]

[asadujjaman]

No help yet! The critical portion of the output is highlighted. Seems video mode error. How can i change the video mode before nexuiz is started? Can I do it in the .config file? What is the command?

[Contents of details.txt]
Console initialized.
Nexuiz Linux 16:37:54 May 30 2007
Trying to load library... "libz.so.1" - loaded.
Compressed files support enabled
Added packfile data/common-spog.pk3 (26 files)
Added packfile data/data20070531.pk3 (3675 files)
Trying to load library... "libcurl.so.4" - loaded.
cURL support enabled
Initializing client
Failed to init SDL joystick subsystem:
Trying to load library... "libvorbis.so.0" - loaded.
Trying to load library... "libvorbisfile.so.3" - loaded.
Ogg Vorbis support enabled
couldn't exec config.cfg
couldn't exec data/campaign.cfg
couldn't exec autoexec.cfg
Starting video system
Video: fullscreen 800x600x32x60hz
Linked against SDL version 1.2.11
Using SDL library version 1.2.11
Failed to set video mode to 800x600: Couldn't find matching GLX visual
Desired video mode fail, trying fallbacks...
Video: fullscreen 800x600x32x60hz
Linked against SDL version 1.2.11
Using SDL library version 1.2.11
Failed to set video mode to 800x600: Couldn't find matching GLX visual
Video: fullscreen 800x600x16x60hz
Linked against SDL version 1.2.11
Using SDL library version 1.2.11
[/Contents of details.txt]