It appears that various defines/macros the most recent acpi patch conflict with the stock aic7xxx SCSI driver (including "ARG_1"). Sending upstream to http://www.sourceforge.net/projects/acpi bug tracker.
fixed in 20020214 release. http://sourceforge.net/tracker/?func=detail&atid=425171&aid=517318&group_id=36832 We'll merge this in to 2.4.17-r5.