not sure if you tried this but here goes
grub in mbr is looking for booting files that you POINTED grub to when you first installed grub on drive 0"s mbr
The easiest way
keep grub in mbr for primary assuming
primary is the big drive
slave is the drive some files are to be taken off
amend your grub menu.lst to show (hd1,0) or where-ever /boot is... for the root command but you may need to trouble shoot unless your memory of the small drive is good
http://www.linuxquestions.org/questi...hreadid=237511 may help especially the trouble shoooter