The interface info which is in the Unattend.txt file is only used to set the Windows network adapter properties well further along in the installation. At the file copy stage you are still using the IP info retrieved from the DHCP server by the DOS boot image (and not using any of the net adapter configurations from the Unattend.txt).
My guess is that there is some adapter setting such as duplex (set in the bios) or network issues (switch settings/packet loss etc) that is happening. Are you connecting the second NIC to the same switch port that the 1st one was plugged into for the test? If not it may be a network issue. If so, it would be a NIC issue. I really doubt it has anything to do with the entries in the Unattend.txt, because they are not even being used at this point.
It is plugged into the same switch on the same port. So that would point to a NIC issue.
I'll take a look at the settings in the BIOS, and I'll see if there have been any updates from IBM that reference any issues related to this.
It was very odd because the failures would always occur after approximately 96% of the setup files for the windows 2003 install had been copied to the bare-metal server. Then it would just sit there and hang, eventually coming back with a message indicating " to try again."
Not sure why it would always be happening at the same point, unless there is a large file or something that is copied at that time. Are both NICs the same type? Are they both onboard? Also, the NICs sometimes have their own little bios you can get into by hitting a key during the boot sequence which is different from the main bios. Not sure about that model, but it is something to look into. Also, do you have another same type of server you can try booting from each NIC? This might isolate the problem to that specific server.