Update to 12.04.1 via UpdateManager crash

So I tried updating my 10.04 LTS to 12.04.1 LTS using the UpdateManger application. It crashed during the "Clean up" phase - meaning the updater program went away and I was returned to my Ubuntu desktop.

Below is the end of the /var/log/dist-upgrade/main.log file which I assume describes the problem.

But what do I do next?

Thanks.

Scott

2012-08-24 03:15:51,310 DEBUG Start checking for obsolete pkgs
2012-08-24 03:15:57,759 DEBUG package 'liblzma1' has unwanted removals, skipping
2012-08-24 03:15:58,143 WARNING _tryMarkObsoleteForRemoval failed for 'liblzma1' (SystemError('E:Error, pkgProble
mResolver::Resolve generated breaks, this may be caused by held packages.',): E:Error, pkgProblemResolver::Resolv
e generated breaks, this may be caused by held packages.)
2012-08-24 03:15:58,595 ERROR not handled expection:
Traceback (most recent call last):

  File "/tmp/tmpchF2gB/precise", line 7, in <module>
    sys.exit(main())

  File "/tmp/tmpchF2gB/DistUpgradeMain.py", line 226, in main
    if app.run():

  File "/tmp/tmpchF2gB/DistUpgradeController.py", line 1721, in run
    return self.fullUpgrade()

  File "/tmp/tmpchF2gB/DistUpgradeController.py", line 1703, in fullUpgrade
    self.doPostUpgrade()

  File "/tmp/tmpchF2gB/DistUpgradeController.py", line 1208, in doPostUpgrade
    if not self.cache.tryMarkObsoleteForRemoval(pkgname, remove_candidates, self.foreign_pkgs):

  File "/tmp/tmpchF2gB/DistUpgradeCache.py", line 204, in wrapper
    res = f(*args, **kwargs)

  File "/tmp/tmpchF2gB/DistUpgradeCache.py", line 978, in tryMarkObsoleteForRemoval
    self.restore_snapshot()

  File "/tmp/tmpchF2gB/DistUpgradeCache.py", line 317, in restore_snapshot
    pkg.mark_delete()

  File "/usr/lib/release-upgrader-python-apt/apt/deprecation.py", line 98, in deprecated_function
    return func(*args, **kwds)

  File "/usr/lib/release-upgrader-python-apt/apt/package.py", line 1245, in mark_delete
    fix.resolve()

SystemError: E:Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages.

2012-08-24 03:15:58,596 DEBUG running apport_crash()
2012-08-24 03:15:58,611 ERROR failed to import apport python module, can't report bug: No module named apport.report
2012-08-24 03:16:00,473 DEBUG enabling apt cron job