Well... there's always the obvious: "File not found" suggests linux is looking in the wrong place for the file. I'm used to grub configs that would looklike this...
title Fedora 3
kernel /boot/vmlinuz-2.6.9-1.667 ro root=LABEL=/ rhgb quiet
however, I'm not sure about dual boot for different distros of linux. Where I've had two kernels, I've just stuck everything in the same boot partition. The above assumes that vmlinuz and initrd are in the directories specified - this should make / = /dev/hdb2 and everything should be relative to that(?)
Now for someone to contradict me