Project Server 2003 won’t work with SharePoint 2010.
Also installing Project 2003 with SBS is not supported way since SBS server has Domain controller, and DC security will block the installer at many places. There are couple of blogs available
on internet to install PSVR 2003 on Win 2003, however it is not supported.
Hrushikesh Deshpande – Senior EPM Infrastructure Consultant, www.DeltaBahn.com