I don't think it would be on the Novell Client Properties, but rather on the programs themselves.
I don't know if compatibility mode would help. It sounds like the program that runs the login script isn't. I don't remember exactly what that is.
Have you tried disabling UAC?
http://www.sevenforums.com/system-security/1212-how-disable-user-account-control-uac-windows-7-a.html
Even though UAC is "nicer" in 7 it's still there. It may be blocking your user from running whatever processes the login script without bugging you about it.
If there are any services the client installs, make sure they aren't using your domain admin user but are running as the local system or network service or whatever they should be set for, to make sure the Windows local security features aren't preventing them from doing anything.
Sorry I can't be more specific, but I'm one of those people that have been avoiding Vista like the plague it is, and will have to be dragged kicking and screaming to Windows 7 well after it's had its first real service pack. I will probably have that option, too, because Microsoft keeps being forced to extend Windows XP availability.
