Upgrade 10.04 -> 12.04 results in "E:Error, pkgProblemResolver::Resolve generated breaks"

[Felix Günther]

Upgrading from 10.04 to 12.04 with

  do-release-upgrad [-d]

fails with

  E:Error, pkgProblemResolver::Resolve generated breaks, this may be
caused by held packages.

I already browsed through dozens of similar bugs on launchpad, but none seemed to apply to my case. A short summary of the things I checked:

 * I purged "xserver-xorg-video-nouveau".
 * I deactivated all ppa repositories and other repositories, the only ones remaining are lucid[-update/-security] main/restricted/universe/multiverse.
 * I updated all packages that were on hold / pinned to a specific version.

Please let me know if you need any further information on the system. Thanks in advance for your support.

ProblemType: Bug
DistroRelease: Ubuntu 10.04
Package: update-manager 1:0.134.12.1
ProcVersionSignature: Ubuntu 2.6.32-43.97-generic 2.6.32.59+drm33.24
Uname: Linux 2.6.32-43-generic i686
Architecture: i386
Date: Thu Sep 27 01:04:36 2012
GConfNonDefault:
 /apps/update-manager/check_new_release_ignore=
 /apps/update-manager/first_run=false
 /apps/update-manager/show_details=false
 /apps/update-manager/show_versions=false
 /apps/update-manager/window_size=(506,600)
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=
 PATH=(custom, user)
 LANG=de_DE.UTF-8
 SHELL=/bin/bash
SourcePackage: update-manager
VarLogDistupgradeAptclonesystemstate.tar.gz: Error: [Errno 13] Keine Berechtigung: '/var/log/dist-upgrade/apt-clone_system_state.tar.gz'

[dino99 (9d9)]

This version is no more supported