postgresql-plperl-8.4' is marked for removal but it is in the removal blacklist.

[John D. West]

attempting to upgrade from 10.04LTS to 12.04LTS, I get the following:
Could not calculate the upgrade

An unresolvable problem occurred while calculating the upgrade:
The package 'postgresql-plperl-8.4' is marked for removal but it is in the removal blacklist.

 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

If none of this applies, then please report this bug using the command 'ubuntu-bug update-manager' in a terminal.

ProblemType: Bug
DistroRelease: Ubuntu 10.04
Package: update-manager 1:0.134.12.1
ProcVersionSignature: Ubuntu 2.6.32-42.96-generic 2.6.32.59+drm33.24
Uname: Linux 2.6.32-42-generic x86_64
Architecture: amd64
Date: Wed Sep 12 18:06:53 2012
InstallationMedia: Ubuntu 10.04 LTS "Lucid Lynx" - Release amd64 (20100429)
PackageArchitecture: all
ProcEnviron:
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/tcsh
SourcePackage: update-manager
VarLogDistupgradeAptclonesystemstate.tar.gz: Error: [Errno 13] Permission denied: '/var/log/dist-upgrade/apt-clone_system_state.tar.gz'
VarLogDistupgradeTermlog: