upgrade from 10.10 to 11.04 impossible

[v3g4]

when executing update-manager -d
an error systematically occurs at the stage where the manager says calculating changes or something like that
I get this message :
E:Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages.
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

I am joining the /var/log/dist-upgrade logs for my latest attempt

[Tim Casey (tjcasey)]

Thanks for taking the time to report your experience with update-manager.

Can you please try the following;

sudo apt-get install aptitude
sudo aptitude update
sudo aptitude upgrade

then retry running update-manager -d

[v3g4 (3d1gg4)]

I worked around it by purging the packages from xorg-edges using ppa-purge. after rebooting I installed 11.04 without any errors. found the solution here: http://ubuntuforums.org/showthread.php?t=1720359