AMD64 panic on boot

I built a custom kernel and it says that it can't map interrupts for
certain devices (like my ATA controller), which prevents it from being
able to find my disks and mount my root fs.

I *think* my kernel configuration is fairly standard. It's available
at http://c133.org/freebsd-7.conf if anybody would mind taking a look
and offering some pointers. I cvsup'd yesterday around midnight, and
my hardware is a pretty standard nforce4 mobo with a dual-core Opteron
for the main CPU.

Thanks!