package lightdm 1.1.4.is.1.1.3-0ubuntu2 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1

Crashed when trying to do apt-get upgrade on a mythbuntu install

ProblemType: Package
DistroRelease: Ubuntu 12.04
Package: lightdm 1.1.4.is.1.1.3-0ubuntu2
ProcVersionSignature: Ubuntu 3.2.0-16.25-generic 3.2.6
Uname: Linux 3.2.0-16-generic i686
NonfreeKernelModules: nvidia
ApportVersion: 1.94-0ubuntu1
Architecture: i386
Date: Mon Mar 5 22:07:03 2012
DuplicateSignature:
 Setting up lightdm (1.1.4.is.1.1.3-0ubuntu2) ...
 No such schema 'org.gnome.settings-daemon.peripherals.touchpad'
 dpkg: error processing lightdm (--configure):
  subprocess installed post-installation script returned error exit status 1
ErrorMessage: subprocess installed post-installation script returned error exit status 1
SourcePackage: lightdm
Title: package lightdm 1.1.4.is.1.1.3-0ubuntu2 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1
UpgradeStatus: Upgraded to precise on 2012-02-17 (17 days ago)