Flybywyre,
It sounds like you do not have the proper WinXP drivers for the SATA RAID.
Are you booting off the RAID Array or a Single Drive?
If you are booting off the RAID, you should have hit F6 during the WinXP Install and loaded the SATA RAID Drivers for WinXP then.
If you did not, then you might want to run a Repair of WinXP with the WinXP CD, and make sure you hit F6 and load the drivers.
Take Care,
Richard