I will update my system from 14.04 to 15.04 but it doesn work.

[Mathias Schröder]

My system informs me that a new version of kubuntu is available. After downloading packages, the updater will start doinf update. Than it stops with an error message.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: ubuntu-release-upgrader-core 1:0.220.8
ProcVersionSignature: Ubuntu 3.13.0-86.130-generic 3.13.11-ckt39
Uname: Linux 3.13.0-86-generic i686
ApportVersion: 2.14.1-0ubuntu3.20
Architecture: i386
CrashDB: ubuntu
Date: Sat May 21 14:30:31 2016
InstallationDate: Installed on 2013-05-01 (1115 days ago)
InstallationMedia: Kubuntu 13.04 "Raring Ringtail" - Release i386 (20130424)
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=de_DE
 TERM=xterm
 PATH=(custom, no user)
 LANG=de_DE.UTF-8
 SHELL=/bin/bash
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to trusty on 2016-05-21 (0 days ago)
VarLogDistupgradeTermlog:

mtime.conffile..etc.update.manager.release.upgrades: 2016-05-05T20:05:47.412351