Upgrade to 10.04 error - "could not determine the upgrade"

[bd10]

Hi forum,

I tried to upgrade 9.10 to 10.04 (desktop, 64 bit, xfce as 2nd environment) via the alternate CD: ubuntu-10.04-alternate-amd64.iso

During the upgrade I was prompted with the below error.

Options (1) and (2) are clearly no applicable.

As for (3), I have medibuntu repositories from which I have installed various plug-ins and a few applications, such as R, youtube-dl, clive, clamscan. Could they be responsible for this message?

In any case, my /etc/apt/sources.list is enclosed below.

What am I doing wrong during the upgrade?

Many thanks,

Bernd
==========
# deb cdrom:[Ubuntu 9.10 _Karmic Koala_ - Release amd64 (20091027)]/ karmic main restricted
# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.

# medibuntu server down till April 21st, mean-time repository:
deb http://mirrors.ucr.ac.cr/medibuntu/ karmic free non-free
deb-src http://mirrors.ucr.ac.cr/medibuntu/ karmic free non-free

deb http://gb.archive.ubuntu.com/ubuntu/ karmic main restricted
deb-src http://gb.archive.ubuntu.com/ubuntu/ karmic main restricted
# deb http://software.rc.fas.harvard.edu/m.../linux/ubuntu/ karmic/
# deb http://cran.at.r-project.org/bin/linux/ubuntu/ karmic/

## Major bug fix updates produced after the final release of the
## distribution.
deb http://gb.archive.ubuntu.com/ubuntu/ karmic-updates main restricted
deb-src http://gb.archive.ubuntu.com/ubuntu/ karmic-updates main restricted

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team. Also, please note that software in universe WILL NOT receive any
## review or updates from the Ubuntu security team.
deb http://gb.archive.ubuntu.com/ubuntu/ karmic universe
deb-src http://gb.archive.ubuntu.com/ubuntu/ karmic universe
deb http://gb.archive.ubuntu.com/ubuntu/ karmic-updates universe
deb-src http://gb.archive.ubuntu.com/ubuntu/ karmic-updates universe

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team, and may not be under a free licence. Please satisfy yourself as to
## your rights to use the software. Also, please note that software in
## multiverse WILL NOT receive any review or updates from the Ubuntu
## security team.
deb http://gb.archive.ubuntu.com/ubuntu/ karmic multiverse
deb-src http://gb.archive.ubuntu.com/ubuntu/ karmic multiverse
deb http://gb.archive.ubuntu.com/ubuntu/ karmic-updates multiverse
deb-src http://gb.archive.ubuntu.com/ubuntu/ karmic-updates multiverse

## Uncomment the following two lines to add software from the 'backports'
## repository.
## N.B. software from this repository may not have been tested as
## extensively as that contained in the main release, although it includes
## newer versions of some applications which may provide useful features.
## Also, please note that software in backports WILL NOT receive any review
## or updates from the Ubuntu security team.
# deb http://gb.archive.ubuntu.com/ubuntu/ karmic-backports main restricted universe multiverse
# deb-src http://gb.archive.ubuntu.com/ubuntu/ karmic-backports main restricted universe multiverse

## Uncomment the following two lines to add software from Canonical's
## 'partner' repository.
## This software is not part of Ubuntu, but is offered by Canonical and the
## respective vendors as a service to Ubuntu users.
# deb http://archive.canonical.com/ubuntu karmic partner
# deb-src http://archive.canonical.com/ubuntu karmic partner

deb http://gb.archive.ubuntu.com/ubuntu/ karmic-security main restricted
deb-src http://gb.archive.ubuntu.com/ubuntu/ karmic-security main restricted
deb http://gb.archive.ubuntu.com/ubuntu/ karmic-security universe
deb-src http://gb.archive.ubuntu.com/ubuntu/ karmic-security universe
deb http://gb.archive.ubuntu.com/ubuntu/ karmic-security multiverse
deb-src http://gb.archive.ubuntu.com/ubuntu/ karmic-security multiverse
===========

[bd10]

Hi all,

it seems to be a bug.

https://bugs.launchpad.net/ubuntu/+s...er/+bug/572439

Regards,

Bernd