Dual-booting
Following this thread on the forums, users have seemed to come up with a Karmic work around for fixing your dual-boot problems...
$ sudo apt-get install --reinstall libdebian-installer4
$ sudo os-prober
$ sudo update-grub
Error 15 - File not found
This error means that while grub2 is installed to /boot your Master Boot Record ( mbr ) still contains grub legacy. This can happen if you don't select your drive when running "sudo update-from-grub-legacy".
#First, obtain a copy of the latest Ubuntu LiveCD and boot it. Please note that the Live CD must be the same as the system you are fixing - either 32-bit or 64-bit (if not then the chroot will fail).
#Open a terminal and type
$ sudo fdisk -l
Now, you need to remember which device listed is your linux distribution, for reference, /dev/sda1 will be used. Now we need to mount the filesystem to /mnt
$ sudo mount /dev/sda1 /mnt
If you have /boot on a separate partition, that need's to be mounted aswell. For reference, /dev/sda2 will be used.
$ sudo mount /dev/sda2 /mnt/boot
#Make sure you don't mix these up, pay attention to the output of FDISK
#Now mount the rest of your devices and some other things needed in the chroot
$ sudo mount --bind /dev /mnt/dev
$ sudo mount --bind /proc /mnt/proc
$ sudo mount --bind /sys /mnt/sys
Now chroot into your system
$ sudo chroot /mnt
# You should be chroot'd into your system as root, you can now run commands as root, without the need for sudo.
#Tell grub what drive it should install itself to (press space bar to select a drive and don't continue without selecting one)
$ dpkg-reconfigure grub-pc
# Press Ctrl+D to exit out of the chroot.
#Once you exit back to your regular console, undo all the mounting
$ sudo umount /mnt/dev
$ sudo umount /mnt/proc
$ sudo umount /mnt/sys
$ sudo umount /mnt
And you should be free to restart your system right into GRUB 2 and then into your system installation.