failed to upgrade natty->oneiric ubuntu-minimal missing

[Mio]

i stasrted update manager from terminal with : sudo update-manager -d
pressed upgrade, upgrade starts, it fails at the setting-up-the-new-repositories step with:
Invalid package information
After your package information was updated the essential package 'ubuntu-minimal' can not be found anymore.
This indicates a serious error, please report this bug using the command 'ubuntu-bug update-manager' in a terminal and include the files in /var/log/dist-upgrade/ in the bug report.

terminal output is just:
extracting 'oneiric.tar.gz'
authenticate 'oneiric.tar.gz' against 'oneiric.tar.gz.gpg'

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: update-manager 1:0.150.3
ProcVersionSignature: Ubuntu 2.6.38-11.49-generic 2.6.38.8
Uname: Linux 2.6.38-11-generic x86_64
NonfreeKernelModules: nvidia
Architecture: amd64
Date: Fri Sep 2 17:36:11 2011
GConfNonDefault:
 /apps/update-manager/check_new_release_ignore=
 /apps/update-manager/first_run=false
 /apps/update-manager/show_details=true
 /apps/update-manager/window_size=(776,735)
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Beta amd64 (20110413)
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=de_DE:en
 LANG=de_DE.UTF-8
 SHELL=/bin/bash
SourcePackage: update-manager
UpgradeStatus: Upgraded to natty on 2011-09-02 (0 days ago)

[Mio (m10)]

below are the files found in /var/log/dist-upgrade/20110902-1739/

[Mio (m10)]

both in /var/log/dist-upgrade/ and in /var/log/dist-upgrade/20110902-1739/ there was a empty term.log file

[Mio (m10)]

it is a (repository) mirror problem.. switching to the main server did
the upgrade.. still annoing and my mum would have never understood it ;)

[Robert Roth (evfool)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. This particular bug has already been reported and is a duplicate of bug #838787, so it is being marked as such. Please look at the other bug report to see if there is any missing information that you can provide, or to see if there is a workaround for the bug. Additionally, any further discussion regarding the bug should occur in the other report. Feel free to continue to report any other bugs you may find.

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