Windows Server 2003 unattended builds are best performed using the Microsoft Server 2003 deployment tools included in the SUPPORT folder on the Server 2003 CD (or download from www.microsoft.com) or nlite, a free tool that manages the creation of an unattended ISO image with a simple wizard interface (www.nliteos.com).

If you have any trouble, try searching the forums at unattended.msfn.org.