RE: Trying to install Windows Server 2003 Standard
Uncheck it for the install from SBUU, then download and install it after Windows is installed. You are usually better off installing from SMTD instead of SBUU.
Using the method you were using before, this is the driver you needed:
With 2003, you need to use a floppy disk at the F6 prompt during Windows Setup, or you need to use nLiteOS.com to integrate the drivers into your installation media.
You really shouldn't be using 2003 any longer.