OK, it looks like you are part way there, but I will cover a few points just in case. If you have more than one NIC in your server, I think there may be issues, as I seem to recall a discussion a long time ago that specified that Ghost would only work with one NIC.
For the version of WinPE included with GSS 2.5.1.2266, you need to use 32 bit VISTA drivers, regardless of the operating system you are imaging. It looks like you have already been pointed in this direction, but I would emphasise the 32 bit aspect, as the WinPE build used is 32 bit. It is unusual for Vista drivers to be made available for a server, as Vista was never released as a server operating system. Trying drivers intended for your chipset under Vista is probably the best way to go.
If you are able to boot the server to a Windows operating system, you can go into device manager via Control Panel, locate the NIC device, and then look for the hardware ID and make a note of it. Your candidate drivers will consist of a .INF .SYS and .CAT file as a minimum, with maybe some DLLs as well. The INF file, if opened in a text editor, should contain at least one hardware ID, and for the drivers to be loaded by the plug and play subsystem, the hardware ID of the NIC must be located in one of the INF files available to the operating system.
Fortunately, WinPE offers a way of loading candidate driver sets from the command line, so that you can test a number of drivers without creating new boot images or even rebooting. See this article for details of how to use DRVLOAD: http://www.symantec.com/business/support/index?page=content&id=TECH122799
Once you have found a driver that allows you to run IPCONFIG /release and /renew successfully, you can then add it via Ghost Boot Wizard, make sure it is selected, and then burn your boot image.