Group policy

i have installed windows 2003 server and kceadsser domain.i have created group policy for student organisation unit.it running in server if we login in the user of student organisational unit,but in client machine its not working.what may be the problem.

Client machine : windows xp,windows 2000 prof
i edited the user configuration of student organisational unit.
administrative templates-system-login script-run these programs at login

administrative templates-system-Desktop-Hide all icons from the desktop