package grub-pc 1.99-21ubuntu3.1 failed to install/upgrade: el subproceso instalado el script post-installation devolvió el código de salida de error 20

[victor alvarado]

Spanish.
cuando actualizo con el gestor de actualizaciones o por medio de consola me sale este error

ProblemType: Package
DistroRelease: Ubuntu 12.04
Package: grub-pc 1.99-21ubuntu3.1
ProcVersionSignature: Ubuntu 3.2.0-24.39-generic-pae 3.2.16
Uname: Linux 3.2.0-24-generic-pae i686
ApportVersion: 2.0.1-0ubuntu8
AptOrdering:
 wmctrl: Install
 window-list: Install
 grub-pc: Configure
 wmctrl: Configure
 window-list: Configure
Architecture: i386
Date: Wed Jun 6 22:05:18 2012
ErrorMessage: el subproceso instalado el script post-installation devolvió el código de salida de error 20
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release i386 (20120423)
ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.2.0-24-generic-pae root=UUID=436b1038-4706-4a7d-b662-5f6c2a3fd8f4 ro quiet splash *pcie_aspm=force pcie_aspm=force
SourcePackage: grub2
Title: package grub-pc 1.99-21ubuntu3.1 failed to install/upgrade: el subproceso instalado el script post-installation devolvió el código de salida de error 20
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Marcus Tomlinson (marcustomlinson)]

This release of Ubuntu is no longer receiving maintenance updates. If this is still an issue on a maintained version of Ubuntu please let us know.

[Launchpad Janitor (janitor)]

[Expired for grub2 (Ubuntu) because there has been no activity for 60 days.]