I had the same problem, but I think it was due to a failing of the upgrade manager during installation. A by-hand "apt-get update" and "dpkg-configure -a" did not all the stuff the update manager would have made I guess. Especially evms was not reinstalled, so that the udevd was making trouble, maybe the restart of changed the permissions of /dev/null - but I am not sure.
A reboot helped and I guess a "sudo chmod 0666 /dev/null" would help too.
I had the same problem, but I think it was due to a failing of the upgrade manager during installation. A by-hand "apt-get update" and "dpkg-configure -a" did not all the stuff the update manager would have made I guess. Especially evms was not reinstalled, so that the udevd was making trouble, maybe the restart of changed the permissions of /dev/null - but I am not sure.
A reboot helped and I guess a "sudo chmod 0666 /dev/null" would help too.
Regards,
sandoz