Windows XP provides no driver support for the Adaptec's AAA-UDMA. Additionally Adaptec provides no driver support for the AAA-UDMA under Windows XP. However, I've found the AAA-UDMA RAID controller to function without error in Windows XP using version 4.40.09 ("44009") of the Win2k drivers available on Adaptec's support site (www.adaptec.com) NOTE: I haven't tested the filter driver or the CI/O Management software under WinXP. Without the filter driver, the AAA-UDMA may not enter "low power" states (sleep mode, hibernation, etc.) properly. Additionally, I STRONGLY recommend that you backup any sensitive data you may be storing on this controller before running it under WinXP, as your results may differ from mine.
http://www.adaptec.com/worldwide/support/driverdetail.html?cat=/Product/AAA-UDMA&filekey=udma_v44009_drv_w2k.exe

Works fine under Windows 2003 Server Enterprise.