Traceback (most recent call last):
  File "/usr/bin/ubiquity-dm", line 557, in <module>
    ret = dm.run(*sys.argv[4:])
  File "/usr/bin/ubiquity-dm", line 458, in run
    db = DebconfCommunicator('ubiquity', cloexec=True)
  File "/usr/lib/ubiquity/ubiquity/debconfcommunicator.py", line 33, in __init__
    write=self.dccomm.stdin)
  File "/usr/lib/python2.7/dist-packages/debconf.py", line 53, in __init__
    self.setUp(title)
  File "/usr/lib/python2.7/dist-packages/debconf.py", line 56, in setUp
    self.version = self.version(2)
  File "/usr/lib/python2.7/dist-packages/debconf.py", line 65, in <lambda>
    lambda *args, **kw: self.command(command, *args, **kw))
  File "/usr/lib/python2.7/dist-packages/debconf.py", line 86, in command
    status = int(status)
ValueError: invalid literal for int() with base 10: ''