Ugh. Should ditch that card - enough time and effort already:
2.6.15-26-server #1 SMP Thu Aug 3 04:09:15 UTC 2006 i686 GNU/Linux
Subsystem: Adaptec AAR-2810SA PCI SATA 8ch
kernel: aacraid: Host adapter reset request. SCSI hang ?
kernel: aacraid: SCSI bus appears hung
kernel: sd 0:0:0:0: scsi: Device offlined - not ready after error recovery
kernel: sd 0:0:0:0: scsi: Device offlined - not ready after error recovery
kernel: sd 0:0:0:0: SCSI error: return code = 0x6000000
Looks like Adaptec is the brand to avoid!
http://www.tcm.phy.cam.ac.uk/~mr349/hardware/disk_controllers.html
Even if IBM sells it :-)
Update - 2009 - So long Adaptec! Running just peachy keen on cheap SATA Promise cards (no hardware raid), plus I get constant monitoring with email notification to boot!