Long story short, try setting the AGP aperture to 32MB and moving the aperture base (APBASE, 0x10-13) to somewhere else, preferably wherever the stock bios moves it to. Even if it's not the root cause, it'll get it out of the way for later.
-Corey
It looks like the original bios alocates the memory region 0xf0000000 - 0xf7ffffff for the Aperture how would I force LinuxBIOS to do this?? Thanks - Joe