Comment 8 for bug 1273524

Also this does not seem to effect the guest session for openbox, but does for lubuntu-netbook session making it more likely this truely is in lxsession.

To reproduce in lubuntu-netbook select guest session as the user in lightdm and in the top panel of lightdm click what by default looks like the lxde logo and change to lubuntu netbook. Then the session logs in and you recieve the error message.