Launching a graphical application fails with error "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."

Issue

• Launching virt-manager on RHEL6 gives following error if launched as root after doing "su root":

  Error starting Virtual Machine Manager: 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: 
  Failed to get connection to session: Failed to connect to socket 
  /tmp/dbus-CvpE8GBr5L: Connection refused)