package postgresql-8.4 8.4.8-0ubuntu0.11.04 failed to install/upgrade: subprocess installed pre-removal script returned error exit status 1

[Pai]

Binary package hint: postgresql-8.4

broken packages after updates

ProblemType: Package
DistroRelease: Ubuntu 11.04
Package: postgresql-8.4 8.4.8-0ubuntu0.11.04
ProcVersionSignature: Ubuntu 2.6.38-9.43-generic 2.6.38.4
Uname: Linux 2.6.38-9-generic i686
NonfreeKernelModules: nvidia
AptOrdering:
 postgresql-client-common: Install
 postgresql-8.4: Remove
 postgresql-client-common: Configure
 postgresql-common: Configure
Architecture: i386
Date: Sat May 21 03:10:57 2011
ErrorMessage: subprocess installed pre-removal script returned error exit status 1
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Release i386 (20110427.1)
SourcePackage: postgresql-8.4
Title: package postgresql-8.4 8.4.8-0ubuntu0.11.04 failed to install/upgrade: subprocess installed pre-removal script returned error exit status 1
UpgradeStatus: No upgrade log present (probably fresh install)