Comment 4 for bug 74165

I believe the cause of the error is that it was trying to install grub on an invalid device. You could try doing (hd2) or /dev/sda instead of (sda) for where to install grub.

Dec 2 09:40:01 ubuntu grub-installer: info: Installing grub on '(sda)'
Dec 2 09:40:01 ubuntu grub-installer: info: grub-install supports --no-floppy
Dec 2 09:40:01 ubuntu grub-installer: info: Running chroot /target /sbin/grub-install --no-floppy "(sda)"
Dec 2 09:40:02 ubuntu grub-installer: Probing devices to guess BIOS drives. This may take a long time.
Dec 2 09:40:02 ubuntu grub-installer: Format of install_device not recognized.
Dec 2 09:40:02 ubuntu grub-installer: Usage: grub-install [OPTION] install_device