Cannot upgrade from 12.02 to 14.01

[Lizma Dunckley]

GUI tells me "new release is available" .. I click "Upgrade.". .. it runs a bit and then stops with an error:

could not calculate the upgrade .. an unresolvable problem occurred while calculating the upgrade ..
it lists 3 causes... and then instructs me to run ubuntu-bug ubuntu-release-upgrader-core in a terminal. .. which I did.

Must I completely wipe my hard disk and do fresh install? How can I find out what is causing the upgrade to fail?

mezzo@lizma-pc $ ubuntu-bug ubuntu-release-upgrader-core
ERROR: hook /usr/share/apport/general-hooks/cloud_archive.py crashed:
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/apport/report.py", line 719, in add_hooks_info
    symb['add_info'](self, ui)
  File "/usr/share/apport/general-hooks/cloud_archive.py", line 18, in add_info
    if '~cloud' in packaging.get_version(package) and \
  File "/usr/lib/python2.7/dist-packages/apport/packaging_impl.py", line 95, in get_version
    raise ValueError('package does not exist')
ValueError: package does not exist
: Fatal IO error: client killed

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: update-manager (not installed)
ProcVersionSignature: Ubuntu 3.2.0-29.46-generic 3.2.24
Uname: Linux 3.2.0-29-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.0.1-0ubuntu17.7
Architecture: amd64
Date: Sat Sep 20 19:21:07 2014
InstallationMedia: Kubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120423)
MarkForUpload: True
ProcEnviron:
 LANGUAGE=en_ZA:en
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_ZA.UTF-8
 SHELL=/bin/bash
SourcePackage: update-manager
Symptom: ubuntu-release-upgrader-core
UpgradeStatus: Upgraded to precise on 2014-09-20 (0 days ago)
VarLogDistupgradeTermlog: