Hey, i have a K8N-DL also running Bios Version 1004.
I got Gentoo 2005.0 x86_64 installed but i had to pass this two parameters to the kernel (2.6.12)
acpi=off
noapic

But i have found a lot stuff regarding the ACPI handling.
I run 4 Maxtor sata drives of the nvidia sata controller.
using raid 0+1 (Linux software Raid)
At the moment, the only bad thing is, i have to push the Power button, to turn off the System.
Everything else, like USB etc is working fine.
Oh i forgot, havn't got sound to work.
Couldn't find the option for the Onboard sound in the kernel config.

I talked to Asus Germany about the ACPI problems and they will pass this to Taiwan (hopefully)
Looks like NUMA is working on the Bios 1004 Version ...
Theres is a option, thats talks about NUMA in the Bios

I found some postes here