Crash on startup: 'NoneType' object has ho attribute 'list_keys'

When I try to start the current version of inticator-weather on my Lucid machine, I get the following traceback:

Traceback (most recent call last):
  File "/usr/bin/indicator-weather", line 1905, in <module>
    wi = indicator_weather()
  File "/usr/bin/indicator-weather", line 914, in __init__
    self.rate = self.settings.get_value("refresh_rate")
  File "/usr/bin/indicator-weather", line 130, in get_value
    if setting_name in self.db.list_keys():
AttributeError: 'NoneType' object has no attribute 'list_keys'

Previously I had no trouble, so apparently changes in the current version introduced a regression somewhere.