Traceback (most recent call last):
  File "/usr/share/software-center/softwarecenter/utils.py", line 90, in wrapper
    f(*args, **kwargs)
  File "/usr/share/software-center/softwarecenter/ui/gtk/softwarepane.py", line 335, in on_application_activated
    self.app_details_view.show_app(app)
  File "/usr/share/software-center/softwarecenter/ui/gtk/appdetailsview_gtk.py", line 1544, in show_app
    self._update_all(self.app_details)
  File "/usr/share/software-center/softwarecenter/ui/gtk/appdetailsview_gtk.py", line 1394, in _update_all
    self._update_usage_counter()
  File "/usr/share/software-center/softwarecenter/ui/gtk/appdetailsview_gtk.py", line 1776, in _update_usage_counter
    self.app_details.desktop_file, _zeitgeist_callback)
  File "/usr/share/software-center/softwarecenter/backend/zeitgeist_simple.py", line 60, in get_usage_counter
    actor=application, interpretation=Interpretation.MODIFY_EVENT.uri)
  File "/usr/lib/pymodules/python2.7/zeitgeist/datamodel.py", line 143, in __getattr__
    raise AttributeError("'%s' object has no attribute '%s'" %(self.__class__.__name__, name))
AttributeError: 'Symbol' object has no attribute 'MODIFY_EVENT'