not able to upgrade to ubuntu 14

[Ida Sprinkhuizen-Kuyper]

Setting new software channels:
Could not calculate the upgrade

An unresolvable problem occurred while calculating the upgrade.

 This can be caused by:
 * Upgrading to a pre-release version of Ubuntu
 * Running the current pre-release version of Ubuntu
 * Unofficial software packages not provided by Ubuntu

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: update-manager 1:0.156.14.22
ProcVersionSignature: Ubuntu 3.2.0-126.169-generic-pae 3.2.79
Uname: Linux 3.2.0-126-generic-pae i686
ApportVersion: 2.0.1-0ubuntu17.15
Architecture: i386
Date: Sat Sep 2 08:44:20 2017
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Release i386 (20111012)
MarkForUpload: True
PackageArchitecture: all
ProcEnviron:
 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 2017-09-02 (0 days ago)
VarLogDistupgradeTermlog: