Traceback (most recent call last):
  File "/usr/lib/python2.6/dist-packages/aptdaemon/gtkwidgets.py", line 386, in _on_clicked
    transaction.cancel()
  File "/usr/lib/python2.6/dist-packages/aptdaemon/client.py", line 288, in cancel
    error_handler=error_handler)
  File "/usr/lib/pymodules/python2.6/dbus/proxies.py", line 140, in __call__
    **keywords)
  File "/usr/lib/pymodules/python2.6/dbus/connection.py", line 620, in call_blocking
    message, timeout)
DBusException: org.freedesktop.DBus.Error.UnknownMethod: Method "Cancel" with signature "" on interface "org.debian.apt.transaction" doesn't exist