Description of problem:
I installed F11 via the KDE x86-64 live cd. Running system-config-services and trying to enable / disable services or start / stop services doesn't result in anything happening. The console shows some backtraces:

# system-config-services
Traceback (most recent call last):
  File "/usr/bin/system-config-services", line 807, in on_serviceDisable_activate
    service.disable ()
  File "/usr/lib/python2.6/site-packages/slip/dbus/polkit.py", line 53, in enable_proxy_wrapper
    sessionbus = dbus.SessionBus ()
  File "/usr/lib/python2.6/site-packages/dbus/_dbus.py", line 219, in __new__
    mainloop=mainloop)
  File "/usr/lib/python2.6/site-packages/dbus/_dbus.py", line 108, in __new__
    bus = BusConnection.__new__(subclass, bus_type, mainloop=mainloop)
  File "/usr/lib/python2.6/site-packages/dbus/bus.py", line 125, in __new__
    bus = cls._new_for_bus(address_or_type, mainloop=mainloop)
dbus.exceptions.DBusException: org.freedesktop.DBus.Error.NoReply: Did not receive a reply. Possible causes include: the remote application did not send a reply, the message bus security policy blocked the reply, the reply timeout expired, or the network connection was broken.