I decided to try 1 other thing which was to use nLite to slipstream WinXP CD including drivers for the card, but that results in the same error when trying to start Windows setup from the boot CD. Maybe Windows setup might load if I could include the drivers by pressing F6 when prompted, i.e. if the system had a floppy drive which it does not.
In my older IDE system I had a sata add-on card that booted just fine with sata optical drives to Windows setup, and there may be some pata adapter card that work too. The question is how many might one have to try before finding one that works. I think I’ll just boot the Windows CD to the sata drive when needed, and at least I can use the pata optical drives once booted to Windows.