Comment 4 for bug 773442

You had far too many packages installed from PPAs (29 PPAs for maverick) to safely upgrade your system. Please install packages from the official repository before upgrading.

The possible candidates that may hold back essential packages and preventing the upgrade are: banshee, libreoffice and xorg-edgers

ppa-purge may help you to revert to official packages.

I'm closing this report because it's not a bug with Ubuntu.