I've been able to reproduce the problem on a fresh lucid with xserver-xorg-video-radeonhd which has been removed from maverick and is blocking the upgrade.
Those who are hit by this bug, could you please try to remove that driver and try performing the upgrade again.
But, following recent discussion with bdmurray on IRC, removing that driver from his system doesn't fix the problem for him, so there is another one.
I've been able to reproduce the problem on a fresh lucid with xserver- xorg-video- radeonhd which has been removed from maverick and is blocking the upgrade.
Those who are hit by this bug, could you please try to remove that driver and try performing the upgrade again.
But, following recent discussion with bdmurray on IRC, removing that driver from his system doesn't fix the problem for him, so there is another one.