do-release-upgrade not works

[Fernando Diaz]

Show errors when I try to upgrade to kubuntu 14.04

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: update-manager 1:0.156.14.17
ProcVersionSignature: Ubuntu 3.2.0-36.57-generic 3.2.35
Uname: Linux 3.2.0-36-generic x86_64
ApportVersion: 2.0.1-0ubuntu17.6
Architecture: amd64
Date: Mon Aug 11 18:02:25 2014
GsettingsChanges:
 com.ubuntu.update-manager first-run false
 com.ubuntu.update-manager launch-time 1394067108
 com.ubuntu.update-manager window-height 600
 com.ubuntu.update-manager window-width 600
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Release amd64 (20110426)
MarkForUpload: True
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=es_UY:en
 TERM=linux
 PATH=(custom, no user)
 LANG=es_UY.UTF-8
 SHELL=/bin/bash
SourcePackage: update-manager
Symptom: ubuntu-release-upgrader-core
UpgradeStatus: Upgraded to precise on 2014-08-11 (0 days ago)