Windows Server 2003 Group Policy Object problem?

I Have a Windows Server 2003 virtual thats set up as a domain controller and I have a client on Win XP virtual vm thats connected to the domain. I am trying to disable the command prompt in the GPO setting in Active Directory and when I enable the "Prevent Access to the Command Prompt" and force the change and the command prompt is disabled on the domain controller and not the client. On the client I just use an ordinary user account. I don't get it. Any ideas?