sndsys is the sound manager (I think), normaly I would advise disabling sound, but as you can\'t run pssetup, I don\'t have a clue.
edit:
Wait, I do have a clue.
Go to C:\\Program Files\\PlaneShift Crystal Blue\\ assuming you installed in that directory of course.
Then open the psclient.cfg file. (there are 3 psclient files, open the one with the shiny colourfull windows logo) Scroll completely down and change this line:
Planeshift.GUI.Skin.Ingame = /this/art/skins/default.zip
to
Planeshift.GUI.Skin.Ingame = /this/art/skins/stone.zip
save the file and launch PS, check if it works, please.