package gdm 3.0.4-0ubuntu15 failed to install/upgrade: subprocess installed post-removal script returned error exit status 128

This happened after a purge and reinstall of gdm. I used "sudo apt-get purge gdm" command.

ProblemType: Package
DistroRelease: Ubuntu 12.04
Package: gdm 3.0.4-0ubuntu15
ProcVersionSignature: Ubuntu 3.2.0-30.48-generic-pae 3.2.27
Uname: Linux 3.2.0-30-generic-pae i686
ApportVersion: 2.0.1-0ubuntu13
AptOrdering: gdm: Purge
Architecture: i386
Date: Wed Sep 19 15:08:15 2012
ErrorMessage: subprocess installed post-removal script returned error exit status 128
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release i386 (20120423.2)
SourcePackage: gdm
Title: package gdm 3.0.4-0ubuntu15 failed to install/upgrade: subprocess installed post-removal script returned error exit status 128
UpgradeStatus: No upgrade log present (probably fresh install)