Unable to install System Control Interrupt handler [20070320]

[jonathan at kc8onw.net]

I just updated to the latest -current from 6.2 release on an amd64 system
and get the below error
ACPI Exception (evevent-0257): AE_ALREADY_EXISTS, Unable to install System
Control Interrupt handler [20070320]

I found this thread that discusses it as well but it seems to have mostly
died off without a clear resolution.
http://lists.freebsd.org/mailman/htdig/freebsd-acpi/2005-December/002307.html

I know the BIOS in this machine is pretty poor but I would like to get it
working.

Thanks for any help,
Jonathan