for casually i mean REALLY casually, 'cause it crash past 30 sec like past 30 minutes... i've copy the terminal messages:

siesh@siesh-desktop:~$ '/home/siesh/planeshift/PlaneShift/psclient'
Your configuration files are in... /home/siesh/.PlaneShift
DEBUG: Initializing OpenAL sound system
DEBUG: Retrieving available devices.
DEBUG: Default OpenAL device: '((sampling-rate 44100) (device '(native))
DEBUG: No device specified
DEBUG: Falling back on default device
DEBUG: Can't retrieve attributes size: OpenAL error ALC_INVALID_DEVICE

planeshift.application.client:
  PlaneShift Steel Blue (0.4.03)
  This game uses Crystal Space Engine created by Jorrit and others
  1.4.0 [Unix-x86-GCC]
Mon May 11 23:50:25 2009, LOG_ANY flag deactivated with no filter.
Mon May 11 23:50:25 2009, LOG_WEATHER flag deactivated with no filter.
Mon May 11 23:50:25 2009, LOG_SPAWN flag deactivated with no filter.
Mon May 11 23:50:25 2009, LOG_CELPERSIST flag deactivated with no filter.
Mon May 11 23:50:25 2009, LOG_PAWS flag deactivated with no filter.
Mon May 11 23:50:25 2009, LOG_GROUP flag deactivated with no filter.
Mon May 11 23:50:25 2009, LOG_CHEAT flag deactivated with no filter.
Mon May 11 23:50:25 2009, LOG_LINMOVE flag deactivated with no filter.
Mon May 11 23:50:25 2009, LOG_SPELLS flag deactivated with no filter.
Mon May 11 23:50:25 2009, LOG_NEWCHAR flag deactivated with no filter.
Mon May 11 23:50:25 2009, LOG_SUPERCLIENT flag deactivated with no filter.
Mon May 11 23:50:25 2009, LOG_EXCHANGES flag deactivated with no filter.
Mon May 11 23:50:25 2009, LOG_ADMIN flag deactivated with no filter.
Mon May 11 23:50:25 2009, LOG_STARTUP flag deactivated with no filter.
Mon May 11 23:50:25 2009, LOG_CHARACTER flag deactivated with no filter.
Mon May 11 23:50:25 2009, LOG_CONNECTIONS flag deactivated with no filter.
Mon May 11 23:50:25 2009, LOG_CHAT flag deactivated with no filter.
Mon May 11 23:50:25 2009, LOG_NET flag deactivated with no filter.
Mon May 11 23:50:25 2009, LOG_LOAD flag deactivated with no filter.
Mon May 11 23:50:25 2009, LOG_NPC flag deactivated with no filter.
Mon May 11 23:50:25 2009, LOG_TRADE flag deactivated with no filter.
Mon May 11 23:50:25 2009, LOG_SOUND flag deactivated with no filter.
Mon May 11 23:50:25 2009, LOG_COMBAT flag deactivated with no filter.
Mon May 11 23:50:25 2009, LOG_SKILLXP flag deactivated with no filter.
Mon May 11 23:50:25 2009, LOG_QUESTS flag deactivated with no filter.
Mon May 11 23:50:25 2009, LOG_SCRIPT flag deactivated with no filter.
Mon May 11 23:50:25 2009, LOG_MARRIAGE flag deactivated with no filter.
Mon May 11 23:50:25 2009, LOG_MESSAGES flag deactivated with no filter.
Mon May 11 23:50:25 2009, LOG_CACHE flag deactivated with no filter.
Mon May 11 23:50:25 2009, LOG_PETS flag deactivated with no filter.
Mon May 11 23:50:25 2009, LOG_USER flag deactivated with no filter.
Mon May 11 23:50:25 2009, LOG_LOOT flag deactivated with no filter.
Mon May 11 23:50:25 2009, LOG_DUELS flag deactivated with no filter.
Mon May 11 23:50:25 2009, LOG_TRIBES flag deactivated with no filter.
Mon May 11 23:50:25 2009, All LOGS are off.
Mounting skin: /this/art/skins/elves.zip
Mounting skin: /planeshift/art/skins/base/client_base.zip
  psEngine initialized.
Using fontsize 16 for resolution 1024x768
WARNING! Object '_s_sigil_03' is not closed!
WARNING! Object 'spikes_06' is not closed!
WARNING! Object 'spikes_04' is not closed!
WARNING! Object '_s_column_01' is not closed!
WARNING! Object 'spikes_02' is not closed!
WARNING! Object '_s_sigil_06' is not closed!
...

crystalspace.graphics3d.shader.fixed:
  Multitexture units: moderate 4

planeshift.application.client:
  PSLoader: step 2: success
Mon May 11 23:51:12 2009, <src/client/pscharcontrol.cpp:880 LoadKeys SEVERE>
Mon May 11 23:51:12 2009, Failed to map 'F10' to 'Brightness reset'
  PSLoader: step 3: success
Mon May 11 23:51:16 2009, <src/common/util/psxmlparser.cpp:282 ParseFile SEVERE>
Mon May 11 23:51:16 2009, Could not find file: /planeshift/world/hydlaa_jayose/sound.xml
Mon May 11 23:51:16 2009, <src/common/util/psxmlparser.cpp:282 ParseFile SEVERE>
Mon May 11 23:51:16 2009, Could not find file: /planeshift/world/terr_common/sound.xml
  PSLoader: step 4: success
Mon May 11 23:51:16 2009, <src/client/psclientdr.cpp:248 HandleStatsUpdate SEVERE>
Mon May 11 23:51:16 2009, Stat request failed because CelClient not ready for EID:53081
Map hydlaa_common loaded successfully in 333ms

crystalspace.collisiondetection.opcode:
  OPCODE WARNING: found 1 degenerate faces in model! Collision might report
  wrong results!
Map hydlaa_plaza loaded successfully in 5778ms
Mon May 11 23:51:22 2009, <src/client/psclientdr.cpp:248 HandleStatsUpdate SEVERE>
Mon May 11 23:51:22 2009, Stat request failed because CelClient not ready for EID:53081

my system:
OS: Ubuntu 8.10 (intrepid)
CPU: Intel Pentium 4 2.40GHz
Ram: 1024Mb
Graphics Card: GeForce FX 5200 128Mb

and i say i've understood nothing of the error, 'cause i don't know anything about planshift and, less then all, linux (i've installed linux like a week ago and i've reinstall it like 10 times before it was ok ) so sorry if the post is useless or i've do something wrong (like post in wrong section or post about an already resolved problem)