There is a good chance that your R2 disk has only SP1, as SP2 was released nearly two years after R2 - and about a year before 2008 was released. As Chris said, SP2 is required for most of the drivers, but it will also be required for ANY version of SBUU that would work on a T310.
I would suggest using nLiteOS.com to integrate the drivers into your installation media - and integrating SP2, if the CD doesn't have it already.
Many legacy programs don't play well with 2008 (and later) User Account Control and folder permission changes in 2008+, so that could be a reason, but that can be overcome usually by installing to a user-created folder rather than letting it install in the default location of C:\Program Files.
If you can't get 2003 installed, I would suggest virtualizing ... install 2008+ (if they have a license) and then run 2003 in a VM. Was the server ordered with an OS or without? If they don't have a license for 2008+, then you could install VMWare ESXi (free), then run 2003 in a VM on that.