I am having a similar problem with installing Mint 5.
I have a 250GB IDE drive, that i would like to use as my / and a terabyte SATA drive that I would like to use for my /home. there is an old XP primary partition on the IDE drive, ~15GB, with my / to be the second partition using almost the rest of the disk( 5GB swap at the end).
Whenever I install, there appear to be no problems, in either seeing either drives or partitions, but when I reboot, i get an error from grub saying "error 22 partition does not exist". if i edit the entry to boot from (hd0,1) i am able to get to a desktop, but only the first time. after that, when i reboot again(after doing some updates) it brings up the splash screen, looks like it is loading, then after a minute or so it kicks me back out to what seems to be a recovery console( i believe it was called bonobo, or something similar along the top of the screen).
During the installs, I have so far been leaving the grub installation in the default location.once it is installed, there are no problems, until that first reboot.
could there a way around this by placing grub in the mbr of the sata drive instead of the IDE?
Any ideas would be greatly appreciated