While attempting to upgrade to Ubuntu 11.10 (Oneiric) from 11.04, do-release-upgrade refused to do anything useful. The only message it felt like delivering was “E:Error, pkgProblemResolver::Resolve generated breaks”. Googling didn’t turn up much, but a forum thread (which I seem to have lost now) suggested (among other attempts) to remove any references to external (3rd party) APT repositories. I thought do-release-upgrade did this by itself, but apparently not …
Commenting out the external repositories in /etc/apt/sources.list and in /etc/apt/sources.list.d/* solved the problem (I had spotify, dropbox and Google Chrome there), allowing do-release-upgrade to do its thing.
I’m having this problem too upgrading from 11.04 to 11.10. Tried your advice but it didn’t fix the issue. Guessing I have some packages installed that are screwing things up as well – it’s a pity they can’t give you a more specific error!
The log file generated in /var/log/dist-upgrade (iirc) will tell you which packages failed, and might help you narrow down the issue! See if that helps!
Yes, the /var/log/dist-upgrade/apt.log file is likely to point to the right direction: check what package is ‘holding back’ the process, it is likely to appear several times by the end of the log. In my case it was kdevelop.
Remove the package and try again. It worked for me.