James,
Which board are you using? The setpci enebles writes in the chipset, but the 82801ca has erase/write protect pins as well that are usually wired to a GPIO line from the superio or to a jumper.
I think it is a oem board, so I don't know where it is from. I did make sure the bios write jump is set, and setpci -d 8086:2480 4e.b=1. BTW, this board is using SST 49LF004 as bios flash. If I can backup the original bios, I can also try the 49LF004.
-Andrew