Traceback (most recent call last):
  File "/usr/lib/pymodules/python2.6/dbus/connection.py", line 579, in msg_reply_handler
    *message.get_args_list()))
  File "/usr/lib/pymodules/python2.6/dbus/bus.py", line 75, in error_cb
    callback('')
  File "/usr/share/software-center/softwarecenter/view/transactionswatcher.py", line 39, in _register_active_transactions_watch
    apt_daemon = aptdaemon.client.get_aptdaemon()
  File "/usr/lib/python2.6/dist-packages/aptdaemon/client.py", line 485, in get_aptdaemon
    False),
  File "/usr/lib/pymodules/python2.6/dbus/bus.py", line 244, in get_object
    follow_name_owner_changes=follow_name_owner_changes)
  File "/usr/lib/pymodules/python2.6/dbus/proxies.py", line 241, in __init__
    self._named_service = conn.activate_name_owner(bus_name)
  File "/usr/lib/pymodules/python2.6/dbus/bus.py", line 183, in activate_name_owner
    self.start_service_by_name(bus_name)
  File "/usr/lib/pymodules/python2.6/dbus/bus.py", line 281, in start_service_by_name
    'su', (bus_name, flags)))
  File "/usr/lib/pymodules/python2.6/dbus/connection.py", line 620, in call_blocking
    message, timeout)
DBusException: org.freedesktop.DBus.Error.Spawn.ChildExited: Launch helper exited with unknown return code 1