OK, you can try this, perhaps you\'ve a corrupted psclient.exe version.
Go to your planeshift directory and move the psclient.exe you\'ll find there to another (safe) location, let\'s say the desktop. When done, delete psclient.exe from planeshift folder (don\'t worry, if anything goes wrong you still have a copy of it on the desktop, right?)
Try then launching the updater again, it should find the file missing and will begin to download a new one, hopefully that one won\'t be corrupted and you\'ll be able to play.
Also, check if there\'s some problems with your computer not meeting the minimum requirements:
Minimum Requirements:
* Windows 98, ME, 2000 or XP, Mac OS X 10.2.6, Linux, FreeBSD or Solaris
* GeForce 2 or higher 3D graphics card
* 1 Ghz CPU
* 512 MB RAM
* 1 GB free disk space
* 56k modem Internet connection
Recommended Requirements:
* Windows XP, Mac OS X 10.2.6, Linux or FreeBSD
* GeForce 4 or higher 3D graphics card
* 2 Ghz CPU
* 1 GB RAM
* 1 GB free disk space
* Broadband Internet connection