If your game constantly starts up in the wrong resolution edit your RavenShield.ini file:
Go to section: [WinDrv.WindowsClient]
and set values to your resolution.
WindowedViewportX=640
WindowedViewportY=480
FullscreenViewportX=640
FullscreenViewportY=480
My game has constantly been starting 800x600 and having problems changing to 1024x768.
I changed these to
FullscreenViewportX=1024
FullscreenViewportY=768
and it fixes the problem. If any one else has simular issues with RvS (or S4) you should consider giving it a shot. Now if only I could aim when I play the game at 1600x1200 
My main menu RVS screen and also the in-game shell screen (where you go to join servers) is out of proportion. This problem started ever since I installed Splinter Cell Chaos Theory.
This is useful thanks, as I have an obscure widescreen resolution. Don't play RvS often at all now, but from time to time the urge comes over me.