Trying to upgrade from 12.04 to 14.04.1

[Branko]

Can't upgrade from 12.04 LTS to 14.04 LTS

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: update-manager 1:0.156.14.17
ProcVersionSignature: Ubuntu 3.5.0-54.81~precise1-generic 3.5.7.33
Uname: Linux 3.5.0-54-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.0.1-0ubuntu17.6
Architecture: amd64
Date: Sat Aug 30 09:51:04 2014
GsettingsChanges:
 com.ubuntu.update-manager first-run false
 com.ubuntu.update-manager launch-time 1408294097
 com.ubuntu.update-manager show-details true
 com.ubuntu.update-manager window-height 766
 com.ubuntu.update-manager window-width 600
InstallationMedia: Ubuntu 12.04.2 LTS "Precise Pangolin" - Release amd64 (20130213)
MarkForUpload: True
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=en_US:en
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: update-manager
Symptom: ubuntu-release-upgrader-core
UpgradeStatus: Upgraded to precise on 2014-08-30 (0 days ago)
VarLogDistupgradeTermlog: