netinst CD won't boot on nforce2 board

[Eric Sproul <esproul@ntelos.net>]

Hi,
I'm trying to install Woody on my new nforce2-based machine.  The board
is a Gigabyte GA-7N400 Pro2, with the nforce2-Ultra400 chipset.  I've
read a post about a similar board:
http://lists.debian.org/debian-boot/2003/debian-boot-200304/msg00471.html

So I whipped up a custom netinst CD using a 2.4.21 kernel, which should
support the nVidia hardware.  However, when I try to boot from this CD,
I get a generic failure just after it notes the 2.88MB emulated floppy. 
All the message says is "System Type-(0F) boot failed".  So I don't even
think it's getting to the kernel since it won't even boot the CD--  I
tried a standard netinst CD and got the same message.

I've already installed WinXP on the box, so I know that booting from the
CDROM does work, I just don't know what it is about the netinst CD that
it doesn't like.  Both should have a standard "El Torito" boot image. 
Google searching and checking multiple Debian list archives has yielded
nothing.  Anyone else seen this?  Any hints?

Thanks,
Eric