reboot and shutdown don't work, suspect acpi

Hi,
    Ever since the recent acpi commits, reboot and shutdown no longer work on my
machine (asus k8v deluxe mobo, athlon 64). The machine gets to "Uptime: 1m34s"
(the time is just made up) and hangs. The only way to fix this is to do a hard
reset by pushing the computer's reset button. Any ideas?

Ken