I use startx, but your suggestion makes no difference.Is your LXDE started from a display manager that starts consolekit as well?
If manually starting it withstartx, could you please try "exec dbus-launch --exit-with-x11 ck-launch-session startlxde" in your ~/.xinitrc to see if that works?
It looks like I have screwed up something in LXDE as I suddenly get Openbox sessions starting up when pressing UP in ee.