I’m having trouble with that build myself, same as 15778. I recommend you flash the router with build 14311, it has proven stable for me.
The LAN interface means that the seting will apply to both wired and wireless interfaces of the router. You can separate these interfaces by creating a virtual interface: http://hotspotsystem.com/deskpro/kb_article.php?ref=6778-RFZX-2714
