Ubuntu upgrade fails

[John Hopkin]

Happens every time, and upgrade cannot proceed.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: update-manager 1:0.156.14.13
ProcVersionSignature: Ubuntu 3.2.0-65.99-generic-pae 3.2.60
Uname: Linux 3.2.0-65-generic-pae i686
NonfreeKernelModules: nvidia
ApportVersion: 2.0.1-0ubuntu17.6
Architecture: i386
CurrentDmesg.txt:
 [ 383.738394] r8169 0000:02:05.0: eth0: link up
 [ 383.738610] ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready
 [ 388.310876] CIFS VFS: default security mechanism requested. The default security mechanism will be upgraded from ntlm to ntlmv2 in kernel release 3.3
 [ 393.952010] eth0: no IPv6 routers present
 [ 1491.126459] ptrace of non-child pid 2883 was attempted by: gdb (pid 3383)
Date: Mon Sep 15 16:53:44 2014
DpkgHistoryLog.txt:

DpkgTerminalLog.txt:

GsettingsChanges:
 com.ubuntu.update-manager first-run false
 com.ubuntu.update-manager launch-time 1410792427
 com.ubuntu.update-manager window-height 518
 com.ubuntu.update-manager window-width 600
InstallationMedia: Ubuntu 12.04.1 LTS "Precise Pangolin" - Release i386 (20120817.3)
MarkForUpload: True
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=en_GB:en
 TERM=xterm-color
 PATH=(custom, no user)
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
SourcePackage: update-manager
Symptom: ubuntu-release-upgrader-core
UpgradeStatus: Upgraded to precise on 2014-09-15 (0 days ago)