package samba4 4.0.0+dfsg1-1ubuntu1 failed to install/upgrade: sub-processo script post-installation instalado retornou estado de saída de erro 255

Trying to install Samba4 for the third time. Always ends with an error. It might help to know that the first installation was aborted because the system crashed (hung up). I don't know if the hung up resulted from installing samba or not (I was reading a pen-drive that had an unsuable directory so, this may be the cause for the hung up, not samba).

ProblemType: Package
DistroRelease: Ubuntu 13.04
Package: samba4 4.0.0+dfsg1-1ubuntu1
ProcVersionSignature: Ubuntu 3.8.0-26.38-generic 3.8.13.2
Uname: Linux 3.8.0-26-generic x86_64
ApportVersion: 2.9.2-0ubuntu8.1
Architecture: amd64
Date: Sun Jul 21 11:20:52 2013
DuplicateSignature: package:samba4:4.0.0+dfsg1-1ubuntu1:sub-processo script post-installation instalado retornou estado de saída de erro 255
ErrorMessage: sub-processo script post-installation instalado retornou estado de saída de erro 255
InstallationDate: Installed on 2013-06-30 (21 days ago)
InstallationMedia: Ubuntu 13.04 "Raring Ringtail" - Release amd64 (20130424)
MarkForUpload: True
SourcePackage: samba4
Title: package samba4 4.0.0+dfsg1-1ubuntu1 failed to install/upgrade: sub-processo script post-installation instalado retornou estado de saída de erro 255
UpgradeStatus: No upgrade log present (probably fresh install)