update-manager crashed with AttributeError in _try_show_release_notes_textview(): 'Window' object has no attribute 'window'

update-manager -d

Upon clicking upgrade to 11.10. Already have 11.10 sources.list/packages from a previously failed do-release-upgrade but /etc/lsb-release still shows 11.04.

ProblemType: Crash
DistroRelease: Ubuntu 11.04
Package: update-manager 1:0.152.19
ProcVersionSignature: Ubuntu 3.0.0-11.18-generic 3.0.4
Uname: Linux 3.0.0-11-generic x86_64
ApportVersion: 1.23-0ubuntu1
Architecture: amd64
Date: Mon Sep 26 19:43:46 2011
ExecutablePath: /usr/bin/update-manager
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Release amd64 (20110426)
InterpreterPath: /usr/bin/python2.7
PackageArchitecture: all
ProcCmdline: /usr/bin/python /usr/bin/update-manager -d
ProcEnviron:
 SHELL=/bin/bash
 PATH=(custom, user)
 LANG=en_US.UTF-8
 LANGUAGE=en_US:en
PythonArgs: ['/usr/bin/update-manager', '-d']
SourcePackage: update-manager
Title: update-manager crashed with AttributeError in _try_show_release_notes_textview(): 'Window' object has no attribute 'window'
UpgradeStatus: Upgraded to natty on 2011-09-25 (0 days ago)
UserGroups: adm admin cdrom dialout lpadmin plugdev sambashare vboxusers
VarLogDistupgradeHistorylog:
 Start-Date: 2011-09-25 21:14:02
 Install: ubuntuone-couch:amd64 (0.3.0-0ubuntu2, automatic)
 Upgrade: firefox-globalmenu:amd64 (7.0+build2+nobinonly-0ubuntu1, 7.0+build2+nobinonly-0ubuntu2), unity-place-applications:amd64 (0.4.6-0ubuntu1, 0.4.8-0ubuntu1), deja-dup:amd64 (19.92-0ubuntu1, 19.92-0ubuntu2), firefox:amd64 (7.0+build2+nobinonly-0ubuntu1, 7.0+build2+nobinonly-0ubuntu2), onboard:amd64 (0.95.1-0ubuntu2, 0.95.1-0ubuntu3), unity-lens-applications:amd64 (0.4.6-0ubuntu1, 0.4.8-0ubuntu1), firefox-gnome-support:amd64 (7.0+build2+nobinonly-0ubuntu1, 7.0+build2+nobinonly-0ubuntu2)
 End-Date: 2011-09-25 21:14:43