imposible upgrade ubuntu 14.04

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When upgrade a new version is carry on, suddenly it a new message that says a error and the upgrade stop

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: ubuntu-release-upgrader-core 1:0.220.8
ProcVersionSignature: Ubuntu 3.13.0-68.111-generic 3.13.11-ckt27
Uname: Linux 3.13.0-68-generic i686
NonfreeKernelModules: nvidia
ApportVersion: 2.14.1-0ubuntu3.19
Architecture: i386
CrashDB: ubuntu
CurrentDesktop: Unity
Date: Tue Nov 17 20:44:16 2015
InstallationDate: Installed on 2015-02-18 (272 days ago)
InstallationMedia: It
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to trusty on 2015-11-17 (0 days ago)
VarLogDistupgradeTermlog:

modified.conffile..etc.update.manager.release.upgrades: [modified]
mtime.conffile..etc.update.manager.release.upgrades: 2015-11-08T13:42:02.502720