update-manager crashed with SystemError in mark_install(): E:Unable to correct problems, you have held broken packages.

Update Manager has been having trouble and offering Partial Upgrade and Close buttons after each Check/refresh.
Partial Upgrade sometimes crashes, so instead I have been applying updates selectively in small batches.
I narrowed the update list down to three mysql-related packages. I got this crash while experimenting with selecting/deselecting among these packages, trying to figure out their inter-dependencies.
I think I was trying to deselect the last remaining selected item, mysql-query-browser when I got the crash.
This issue is likely related to the fact that I have done an install from source of mysql version 5.5.14 -- that probably post-dates the default version for the release.

ProblemType: Crash
DistroRelease: Ubuntu 11.10
Package: update-manager 1:0.152.18
ProcVersionSignature: Ubuntu 3.0.0-10.16-generic 3.0.4
Uname: Linux 3.0.0-10-generic i686
ApportVersion: 1.23-0ubuntu1
Architecture: i386
Date: Tue Sep 20 16:40:18 2011
ExecutablePath: /usr/bin/update-manager
InstallationMedia: Xubuntu 11.10 "Oneiric Ocelot" - Beta i386 (20110901)
InterpreterPath: /usr/bin/python2.7
PackageArchitecture: all
ProcCmdline: /usr/bin/python /usr/bin/update-manager
ProcEnviron:
 PATH=(custom, user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
PythonArgs: ['/usr/bin/update-manager']
SourcePackage: update-manager
Title: update-manager crashed with SystemError in mark_install(): E:Unable to correct problems, you have held broken packages.
UpgradeStatus: Upgraded to oneiric on 2011-09-19 (1 days ago)
UserGroups: adm admin cdrom dialout lpadmin plugdev sambashare