no puedo actualizar la version ubuntu

[myriam carsen]

cuando quiero descargar la actualización de ubuntu no lo permite dice que podría tener una versión no autorizada lo cual no es así.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: update-manager 1:0.156.14.11
ProcVersionSignature: Ubuntu 3.2.0-56.86-generic-pae 3.2.51
Uname: Linux 3.2.0-56-generic-pae i686
ApportVersion: 2.0.1-0ubuntu17.6
Architecture: i386
Date: Thu Nov 14 12:51:46 2013
GsettingsChanges:
 com.ubuntu.update-manager check-new-release-ignore 'quantal'
 com.ubuntu.update-manager first-run false
 com.ubuntu.update-manager launch-time 1384440379
 com.ubuntu.update-manager window-height 500
 com.ubuntu.update-manager window-width 600
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release i386 (20120423)
MarkForUpload: True
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=es_AR:es
 TERM=xterm
 PATH=(custom, no user)
 LANG=es_AR.UTF-8
 SHELL=/bin/bash
SourcePackage: update-manager
Symptom: ubuntu-release-upgrader-core
UpgradeStatus: Upgraded to precise on 2013-11-14 (0 days ago)
VarLogDistupgradeAptclonesystemstate.tar.gz: Error: [Errno 13] Permiso denegado: '/var/log/dist-upgrade/apt-clone_system_state.tar.gz'
VarLogDistupgradeTermlog:

[Brian Murray (brian-murray)]

This is due to the package xserver-xorg-video-intel being installed from a PPA and the release upgrader being unable to calculate the upgrade because of this.