package otrs2 3.2.9-2 failed to install/upgrade: subprocess installed post-installation script returned error exit status 255

error while installing otrs .. system freezed

ProblemType: Package
DistroRelease: Ubuntu 13.10
Package: otrs2 3.2.9-2
ProcVersionSignature: Ubuntu 3.11.0-13.20-generic 3.11.6
Uname: Linux 3.11.0-13-generic x86_64
ApportVersion: 2.12.5-0ubuntu2.1
AptOrdering:
 unity-webapps-facebookmessenger: Install
 otrs2: Configure
 otrs: Configure
 unity-webapps-facebookmessenger: Configure
Architecture: amd64
Date: Mon Nov 18 04:57:45 2013
DuplicateSignature: package:otrs2:3.2.9-2:subprocess installed post-installation script returned error exit status 255
ErrorMessage: subprocess installed post-installation script returned error exit status 255
InstallationDate: Installed on 2013-11-16 (3 days ago)
InstallationMedia: Ubuntu 13.10 "Saucy Salamander" - Release amd64 (20131016.1)
MarkForUpload: True
PackageArchitecture: all
SourcePackage: otrs2
Title: package otrs2 3.2.9-2 failed to install/upgrade: subprocess installed post-installation script returned error exit status 255
UpgradeStatus: No upgrade log present (probably fresh install)