package postgresql-client-9.3 9.3.5-0ubuntu0.14.04.1 failed to install/upgrade: le sous-processus script pre-removal installé a retourné une erreur de sortie d'état 2

can't uninstall postgres from ubuntu 14.04

ProblemType: Package
DistroRelease: Ubuntu 14.04
Package: postgresql-client-9.3 9.3.5-0ubuntu0.14.04.1
ProcVersionSignature: Ubuntu 3.13.0-45.74-generic 3.13.11-ckt13
Uname: Linux 3.13.0-45-generic x86_64
NonfreeKernelModules: wl
ApportVersion: 2.14.1-0ubuntu3.6
AptOrdering:
 postgresql-9.3: Purge
 postgresql-client-9.3: Purge
 postgresql-common: Purge
 postgresql-client-common: Purge
Architecture: amd64
Date: Tue Feb 10 16:58:56 2015
DuplicateSignature: package:postgresql-client-9.3:9.3.5-0ubuntu0.14.04.1:le sous-processus script pre-removal installé a retourné une erreur de sortie d'état 2
ErrorMessage: le sous-processus script pre-removal installé a retourné une erreur de sortie d'état 2
InstallationDate: Installed on 2014-12-05 (67 days ago)
InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140417)
SourcePackage: postgresql-9.3
Title: package postgresql-client-9.3 9.3.5-0ubuntu0.14.04.1 failed to install/upgrade: le sous-processus script pre-removal installé a retourné une erreur de sortie d'état 2
UpgradeStatus: No upgrade log present (probably fresh install)