package samba4 4.0.0~alpha18.dfsg1-4ubuntu2 failed to install/upgrade: o subproceso script post-installation instalado devolveu o estado de saída de erro 126

[Manuel Souto Pico]

$ sudo apt-get install samba4
...
ERROR: Invalid smb.conf
/var/lib/dpkg/info/samba4.postinst: 14: /var/lib/dpkg/info/samba4.postinst: /usr/share/samba/setoption.pl: Permission denied
dpkg: erro ao procesar samba4 (--configure):
 o subproceso script post-installation instalado devolveu o estado de saída de erro 126
E: Sub-process /usr/bin/dpkg returned an error code (1)

ProblemType: Package
DistroRelease: Ubuntu 12.04
Package: samba4 4.0.0~alpha18.dfsg1-4ubuntu2
ProcVersionSignature: Ubuntu 3.8.0-29.42~precise1-generic 3.8.13.5
Uname: Linux 3.8.0-29-generic i686
ApportVersion: 2.0.1-0ubuntu17.4
Architecture: i386
Date: Wed Jan 29 13:02:10 2014
DuplicateSignature: package:samba4:4.0.0~alpha18.dfsg1-4ubuntu2:o subproceso script post-installation instalado devolveu o estado de saída de erro 126
ErrorMessage: o subproceso script post-installation instalado devolveu o estado de saída de erro 126
InstallationMedia: Ubuntu 12.04.3 LTS "Precise Pangolin" - Release i386 (20130820.1)
MarkForUpload: True
SourcePackage: samba4
Title: package samba4 4.0.0~alpha18.dfsg1-4ubuntu2 failed to install/upgrade: o subproceso script post-installation instalado devolveu o estado de saída de erro 126
UpgradeStatus: No upgrade log present (probably fresh install)