Applied the fix to a second machine today, the map commands were necessary on this machine. Full text was:
title Windows XP
rootnoverify (hd1,0)
map (hd0) (hd1)
map (hd1) (hd0)
chainloader (hd1)+1
Config was:
SATA0: Enterprise Linux 3.0 with grub (from Powerquest drive image. Bootable 80 Gb image)
SATA1: Windows XP Pro. (From CD, was only hdd in machine during install)
Also checkout http://www.gentoo.org/doc/en/grub-error-guide.xml
Problem 16 was got me going.