Cannot calcuate upgrade on postgresql-plperl-8.4

While attempting to perform 11.10 → 12.04 upgrade I got the following error. My system has been upgraded a few times since installation.

Once I remove this package ( dpkg --remove postgresql-plperl-8.4) upgrade proceeded

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.ve

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: update-manager 1:0.152.25.8
ProcVersionSignature: Ubuntu 3.0.0-16.29~ppa1-generic-tuxonice 3.0.20
Uname: Linux 3.0.0-16-generic-tuxonice x86_64
NonfreeKernelModules: nvidia
ApportVersion: 1.23-0ubuntu4
Architecture: amd64
Date: Wed Mar 21 23:24:20 2012
EcryptfsInUse: Yes
InstallationMedia: Ubuntu 9.10 "Karmic Koala" - Release amd64 (20091027)
PackageArchitecture: all
ProcEnviron:
 PATH=(custom, user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: update-manager
UpgradeStatus: Upgraded to oneiric on 2012-03-21 (0 days ago)