command not found crashes with "bad marshal data"

This is similar to bug 589262 but with a newer version of command-not-found and Ubuntu.

command-not-found version: 0.3
Python version: 3.2.3 final 0
Distributor ID: Ubuntu
Description: Ubuntu 12.10
Release: 12.10
Codename: quantal
Exception information:

bad marshal data (unknown type code)
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/CommandNotFound/util.py", line 24, in crash_guard
    callback()
  File "/usr/lib/command-not-found", line 86, in main
    cnf = CommandNotFound(options.data_dir)
  File "/usr/lib/python3/dist-packages/CommandNotFound/CommandNotFound.py", line 130, in __init__
    self.sources_list = self._getSourcesList()
  File "/usr/lib/python3/dist-packages/CommandNotFound/CommandNotFound.py", line 170, in _getSourcesList
    from aptsources.sourceslist import SourcesList
  File "/usr/lib/python3/dist-packages/aptsources/sourceslist.py", line 37, in <module>
    from apt.deprecation import function_deprecated_by
  File "/usr/lib/python3/dist-packages/apt/__init__.py", line 24, in <module>
    from apt.package import Package
  File "/usr/lib/python3/dist-packages/apt/package.py", line 22, in <module>
    import http.client
  File "/usr/lib/python3.2/http/client.py", line 69, in <module>
    import email.parser
  File "/usr/lib/python3.2/email/parser.py", line 12, in <module>
    from email.feedparser import FeedParser
  File "/usr/lib/python3.2/email/feedparser.py", line 27, in <module>
    from email import message
  File "/usr/lib/python3.2/email/message.py", line 17, in <module>
    from email import utils
  File "/usr/lib/python3.2/email/utils.py", line 33, in <module>
    from email._parseaddr import quote
  File "/usr/lib/python3.2/email/_parseaddr.py", line 16, in <module>
    import time, calendar
  File "/usr/lib/python3.2/calendar.py", line 9, in <module>
    import datetime
ValueError: bad marshal data (unknown type code)