failed to update from ubuntu 11.04 to 11.10

[mario frei]

when i try to update form 11.04 to 11.10 the following message appears:

Es konnte nicht ermittelt werden, welche Systemaktualisierungen verfügbar sind

An unresolvable problem occurred while calculating the upgrade:
E:Fehler: Unterbrechungen durch pkgProblemResolver::Resolve hervorgerufen; dies könnte durch zurückgehaltene Pakete verursacht worden sein.

 This can be caused by:
 * Upgrading to a pre-release version of Ubuntu
 * Running the current pre-release version of Ubuntu
 * Unofficial software packages not provided by Ubuntu

If none of this applies, then please report this bug using the command 'ubuntu-bug update-manager' in a terminal.

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: update-manager 1:0.150.3
ProcVersionSignature: Ubuntu 2.6.38-11.50-generic 2.6.38.8
Uname: Linux 2.6.38-11-generic x86_64
NonfreeKernelModules: nvidia
Architecture: amd64
Date: Mon Oct 17 13:09:46 2011
GConfNonDefault: /apps/update-manager/check_new_release_ignore=
InstallationMedia: Ubuntu 10.04 LTS "Lucid Lynx" - Release amd64 (20100429)
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=de_CH:en
 PATH=(custom, no user)
 LANG=de_CH.UTF-8
 SHELL=/bin/bash
SourcePackage: update-manager
UpgradeStatus: Upgraded to natty on 2011-10-17 (0 days ago)

[Jean-Baptiste Lallement (jibel)]

Thanks for taking the time to report this bug and helping to make Ubuntu better. Could you please add the log files from '/var/log/dist-upgrade/' to this bug report as separate attachments? Thanks in advance.

[mario frei (mario-frei)]

and the term.log file is empty

[Jean-Baptiste Lallement (jibel)]

Could you please remove libcupsys2 and tell if it helps with the upgrade ?
Write down the packages that are removed so you can reinstall them later (note that your printer driver cnijfilter may not be reinstallable)

[mario frei (mario-frei)]

after removing libcupsys2, the update i could successfully complete the update. and ubuntu 11.10 runs smooth.
thank you very much