Check out this page at www.winoscentral.com
http://www.winoscentral.com/windowsxp/error-asus.php
Since XP was built on the W2K core, it looks like it was a legacy problem.
I say was, because the "gold" version of XP does include a Promise Driver in the setup boot files.
3 options:
1. Temporarily connect the drives to the ATA66 interface as the article suggests.
2. Modify the boot floppy to include the W2K Promise driver.
3. Start with an XP startup floppy set.
I don't know if this will work, but you could try booting from floppy with the XP floppy startup files. (you can download the file to create the floppy set from Microsoft)
And then run setup from your W2K CD.
I have 2 of these ASUS boards and like the drive flexability.
I have my system drive on the Promise primary.
A hot-swap bay on the secondary.
My CD-ROM on the ATA66 primary (as slave)
My CD-RW and DVD drive on the ATA66 secondary.
Just a side note, I was not able to get mine to boot with a CD drive as Master on the ATA66 Primary.
Chas