Just put this in your psclient.cfg and it should fix your resolution prob.

; Width/height of CrystalSpace visual
Video.ScreenWidth = 800
Video.ScreenHeight = 600
; Screen depth (currently supports 8, 15, 16, and 32 bits, NO 24 bits!)
Video.ScreenDepth = 32
; Use full-screen mode if available
Video.FullScreen = yes