do-release-upgrade crashed with IOError: [Errno 5] Input/output error

[marcobra (Marco Braida)]

Description: Ubuntu precise (development branch)
Release: 12.04

update-manager-core:
  Installato: 1:0.156.8
  Candidato: 1:0.156.8
  Tabella versione:
 *** 1:0.156.8 0
        500 http://archive.ubuntu.com/ubuntu/ precise/main i386 Packages
        100 /var/lib/dpkg/status

I was updating, daily update/upgrade ( i was not performing any do-release-upgrade) my pc using terminal:

sudo apt-get update; sudo apt-get upgrade; sudo apt-get dist-upgrade

ProblemType: Crash
DistroRelease: Ubuntu 12.04
Package: update-manager-core 1:0.156.8
ProcVersionSignature: Ubuntu 3.2.0-18.29-generic-pae 3.2.9
Uname: Linux 3.2.0-18-generic-pae i686
ApportVersion: 1.94.1-0ubuntu2
Architecture: i386
Date: Thu Mar 15 08:31:20 2012
ExecutablePath: /usr/bin/do-release-upgrade
ExecutableTimestamp: 1331650969
GsettingsChanges:
 com.ubuntu.update-manager first-run false
 com.ubuntu.update-manager launch-time 1329378483
 com.ubuntu.update-manager window-height 882
 com.ubuntu.update-manager window-width 600
InterpreterPath: /usr/bin/python2.7
ProcCmdline: /usr/bin/python /usr/lib/update-manager/check-new-release -q
ProcCwd: /
ProcEnviron:
 TERM=linux
 PATH=(custom, no user)
PythonArgs: ['/usr/lib/update-manager/check-new-release', '-q']
SourcePackage: update-manager
Title: do-release-upgrade crashed with IOError: [Errno 5] Input/output error
Traceback: IOError: [Errno 5] Input/output error
UpgradeStatus: Upgraded to precise on 2012-03-12 (3 days ago)
UserGroups: