This is the error
/usr/share/system-config-firewall/fw_gui.py:59: GtkWarning: Error parsing gtk-icon-sizes string:
xml = gtk.glade.XML(DATADIR + "/" + GLADE_NAME, domain=DOMAIN)
2009-12-10 18:09:00,178 ERROR system-config-network Introspect error on :1.65:/org/fedoraproject/Config/Firewall: 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.
2009-12-10 18:09:00,192 DEBUG system-config-network Executing introspect queue due to error