History :

I originally installed gentoo using hdb1 for the root file system and hda2 for the boot folder, including grub. It worked fine.
I moved the /boot folder to /dev/hdb1 and changed the grub.conf file to conform. I reformatted the hda drive to only have a 2gb swap partition as hda1 and a 4.5gb ext2 partition as hda2. It is currently empty.

I edited fstab to remove the mount of /boot on hda2
I edited grub.conf to change the kernel location from hd0,1 to hd1,0 (hd0,1 = hda2 and hd1,0 = hdb1)

I rebooted to be greeted with the Error 15 noted below. Using the grub boot diskette I had handy I got into the system with the following:

root (hd1,0)
kernel (hd1,0)/boot/kernel-2.6.3
boot

worked fine to boot into gentoo.

I then ran grub:
root (hd1,0)
setup (hd1,0)/boot/kernel-2.6.3

it claimed to have written the mbr correctly.

rebooted to the same error 15.

Ran through the grub-install issues below, finally got that working, and now reboot to the same error 15.

Still looking into it.

UPDATE: 3/18/04 - Grub will not work if loaded onto the slave drive and not the master drive. Doh!
I even went so far as to booting to a Win98 boot diskette and reloading the mbr with fdisk. Same results. Upgraded Grub to the new .94 beta version and reinstalled from scratch - no good. Finally Brian mentioned that 'oh yeah, Grub requires that it be installed to the mbr of the master drive.' Argh. Oh well - at least I know now. Plus I learned a lot about grub. ;)

I'll eventually install something else on that drive, at which time I will make it the grub master and add the gentoo installation to it.

Why don't I physically switch drives? Because there is a padlock on the case and we can't seem to find the key.