Howto: fix Gconf error from Firefox

An error occurred while loading or saving configuration information for firefox. Some of your configuration settings may not work properly.

If you click on details of that error you may see:

Failed to contact configuration server; some possible causes are that you need to enable TCP/IP networking for ORBit, or you have stale NFS locks due to a system crash. See http://projects.gnome.org/gconf/ for information. (Details –  1: Server ping error: IDL:omg.org/CORBA/COMM_FAILURE:1.0)
The fix for this issue may be:

1.  CTRL+ALT+Backspace to log out of the current desktop session.

2. Open a terminal. CTRL+ALT+F1

3. login as root

4.  cd to /tmp/

5. rm -rf  X0-lock

The cause may be that you deleted the contents, or some program or installer deleted the contents of your system’s tmp folder.