grub-installer failed on entire installation

[Paco Molinero]

During the installation of quantal image of Xubuntu grub-installer failed.
The installation was made on VirtualBox

ProblemType: Bug
DistroRelease: Ubuntu 12.10
Package: ubiquity 2.12.0
ProcVersionSignature: Ubuntu 3.5.0-15.22-generic 3.5.4
Uname: Linux 3.5.0-15-generic i686
ApportVersion: 2.5.2-0ubuntu4
Architecture: i386
CasperVersion: 1.324
Date: Thu Sep 20 20:41:17 2012
InstallCmdLine: file=/cdrom/preseed/xubuntu.seed boot=casper initrd=/casper/initrd.lz quiet splash -- maybe-ubiquity
LiveMediaBuild: Xubuntu 12.10 "Quantal Quetzal" - Alpha i386 (20120920)
ProcEnviron:
 LANGUAGE=es_ES.UTF-8
 TERM=linux
 PATH=(custom, no user)
 LANG=es_ES.UTF-8
SourcePackage: grub-installer
UpgradeStatus: No upgrade log present (probably fresh install)

[Paco Molinero (franciscomol)]

Dialog:

Bootloader install failed

Sorry, an error occurred and it was not possible to install the bootloader a the specified location.

How would you like to proceed?

* Choose a different device to install the bootloader on:

    /dev/sda

[Ubuntu QA Website (ubuntuqa)]

This bug has been reported on the Ubuntu ISO testing tracker.

A list of all reports related to this bug can be found here:
http://iso.qa.ubuntu.com/qatracker/reports/bugs/1053565