services_captiveportal.php suggest default auth_method, and old links
If don't select radio button for "Authentication method" it stays empty
so no authentication is default. (auth_method is none.)
Show the radio for it -- that is show the default selection.
Then click Continue should just work then.
Or if you really want this to be selected make sure setHelp text says so.
While there the docs links to services_captiveportal_mac.php
but that redirects to services_captiveportal_zones.php
(What is _mac page?) Fix links?
(I noticed this while working on my book.
My list of bugs is at http://reedmedia.net/books/pfsense/bugs.html )