Traceback (most recent call last):
  File "/usr/lib/pymodules/python2.6/deluge/ui/gtkui/systemtray.py", line 325, in on_menuitem_quit_activate
    client.shutdown()
  File "/usr/lib/pymodules/python2.6/deluge/ui/client.py", line 345, in shutdown
    self.core.call("shutdown", None)
  File "/usr/lib/pymodules/python2.6/deluge/ui/client.py", line 124, in call
    raise deluge.error.NoCoreError("The core proxy is invalid.")
NoCoreError: 'The core proxy is invalid.'