Windows Security Messages XP

Does anyone know how to disable the security messages that come up in XP.
I am running the latest Novell Client and have chosen not to list a default Windows username. This forces the user to log on to the workstation as well as the server.
Problem come up that I get a pop up window that states:
WINDOWS SECURITY WARNING
Your user account has been disabled.
Contact your System Administrator
I know it is seeing the Novell Login as the default Windows XP Guest user account and therefore causing the error message to pop up. How do I get rid of it??