package samba4 4.0.0~alpha18.dfsg1-4ubuntu2 failed to install/upgrade: subprocess installed post-installation script returned error exit status 126

[JZ]

this is an installation failure (sudo apt-get install samba4)

ProblemType: Package
DistroRelease: Ubuntu 12.04
Package: samba4 4.0.0~alpha18.dfsg1-4ubuntu2
ProcVersionSignature: Ubuntu 3.5.0-23.35~precise1-generic 3.5.7.2
Uname: Linux 3.5.0-23-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.0.1-0ubuntu17.1
Architecture: amd64
Date: Thu Mar 21 00:34:02 2013
ErrorMessage: subprocess installed post-installation script returned error exit status 126
InstallationMedia: Ubuntu 12.04.2 LTS "Precise Pangolin" - Release amd64 (20130213)
MarkForUpload: True
SourcePackage: samba4
Title: package samba4 4.0.0~alpha18.dfsg1-4ubuntu2 failed to install/upgrade: subprocess installed post-installation script returned error exit status 126
UpgradeStatus: No upgrade log present (probably fresh install)