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

[Daniel Brown]

Release 12.04 (precise) 64-bit
Kernel Linux 3.5.0-28-generic
Running the Unity shell

I'm new to Linux so I don't really understand much. I tried to install the SAMBA4 package and the install crashed. An error message appeared: 'Error: opening the cache (E:read error - read (5: Input/Output error) E: the package lists or status file could not be parsed or opened.) This usually means that your installed packages have unmet dependencies.'

Please advise as to what I should do next.

ProblemType: Package
DistroRelease: Ubuntu 12.04
Package: samba4 4.0.0~alpha18.dfsg1-4ubuntu2
ProcVersionSignature: Ubuntu 3.5.0-28.48~precise1-generic 3.5.7.9
Uname: Linux 3.5.0-28-generic x86_64
ApportVersion: 2.0.1-0ubuntu17.2
Architecture: amd64
Date: Mon May 13 10:11:10 2013
ErrorMessage: subprocess installed post-installation script returned error exit status 126
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)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.