Working on an install of kubuntu that is farily non-standard and my lvm configuration caused grub to go totally insane. So are some notes I am posting from the live CD (that doesn’t have lvm configured.)
If separate /boot
$ sudo mount /dev/mapper/Qmail-root /mnt
$ sudo mount /dev/sda1 /mnt/boot
$ grub-install –root-directory=/mnt /dev/sda
And here and here are some specific grub2 install information for Ubuntu.