When following the following article http://support.microsoft.com/kb/325379
Started at Overview: Upgrading Windows 2000 domain controllers to Windows Server 2003.
All worked really well till running winnt32.exe /checkupgradeonly. The system tells me that upgrading from 2000 to 2003 Enterprise is not possible. Ouch! Any thoughts on migrating my AD to the new 2003 server. Went with enterprise because of CAL's included.