I deleted everything and now tried just creating the login form using Webassist >> Forms >> Insert New Form.
Preset = Log in, Secure Login (I removed the question from the login form, but everything else is as is). This one is redirecting, but as soon as index.php has rules applied to it, it redirects me back to the login page. Also, it doesn't even appear to be interacting with a database table...???
My code is attached.