The unlock buttons on Users and Groups or Network are greyed out and un-accessible. Tried running from a term 'sudo users-admin' with the same results.

To correct the problem follow this steps:
 - Copy nx-session-launcher and nx-session-launcher-suid to /usr/bin
 - Execute $ chown nx /usr/bin/nx-session-launcher-suid
 - Execute $ chmod 4755 /usr/bin/nx-session-launcher-suid
 - Copy ConsoleKit-NX.conf to /etc/dbus-1/system.d/
 - Reload dbus by issuing /etc/init.d/dbus reload
 - Edit /etc/nxserver/node.conf and change '#COMMAND_START_GNOME=gnome-session'
     to 'COMMAND_START_GNOME=/usr/bin/nx-session-launcher-suid gnome-session'
