Windows 2003 Domain\Windows XP Issue

I have a windows 2003 SP1 domain controler. I joined a windows XP SP2 laptop to the domain. When I log onto the domain from the laptop, the user account does not have administrative rights on the laptop, i.e. cannot install software etc. The user account is a memmebr of the Administrators group for the domain. I am not sure if this is a domain issue on the server on an xp issue. How do I get the user to have local admin rights?
Thanks
Pat