Comment 2 for bug 1309876

Same problem. Just upgraded to Ubuntu 14.04 and tried to use mcomix and it crashed.
Here's the error message I get, looks the same as the one by Turgon.

03:04:21 WARNING: Non-supported archive format: xxx.cbr
Traceback (most recent call last):
  File "/usr/bin/mcomix", line 9, in <module>
    load_entry_point('mcomix==1.00', 'console_scripts', 'mcomix')()
  File "/usr/lib/python2.7/dist-packages/mcomix/run.py", line 200, in run
    open_path = open_path, open_page = open_page)
  File "/usr/lib/python2.7/dist-packages/mcomix/main.py", line 71, in __init__
    self.filehandler = file_handler.FileHandler(self)
  File "/usr/lib/python2.7/dist-packages/mcomix/file_handler.py", line 64, in __init__
    self.last_read_page = last_read_page.LastReadPage(backend.LibraryBackend())
  File "/usr/lib/python2.7/dist-packages/mcomix/library/backend.py", line 646, in LibraryBackend
    _backend = _LibraryBackend()
  File "/usr/lib/python2.7/dist-packages/mcomix/library/backend.py", line 58, in __init__
    self._upgrade_database(version, _LibraryBackend.DB_VERSION)
  File "/usr/lib/python2.7/dist-packages/mcomix/library/backend.py", line 587, in _upgrade_database
    lastread.migrate_database_to_library(COLLECTION_RECENT)
  File "/usr/lib/python2.7/dist-packages/mcomix/last_read_page.py", line 196, in migrate_database_to_library
    book.get_backend = lambda: self.backend
AttributeError: 'NoneType' object has no attribute 'get_backend'