I am having the same sort of problem and more. I have a custom themed WP site which I downloaded with multiple plugins and one of them is Register Plus. My Register Plus settings is not showing ALL customizable values that is supposed to be included like custom registration fields and disclaimer. Also when I try to enable fields and click on Save, it is not saving. Per my reading of posting, I deactivated all of my other plug-ins, deleted and deployed Register Plus , made sure the chown and chmoded correctly but still the same problem.
In addition, I created a "sand-box" type of WP and have only Register plus as the only plug in but still have the same problem.
The only configurable fields showing up in my REgister setting page are:
Password, Custom Logo, Email Verification, Admin Verification, Invitation COde and CAPTCHA.
None of them are working when enabled due to maybe the values are not being saved.
Please somebody help me..I am lost what else to do and I have read each individual posting related to this. I really really really appreciate it. THe site is scheduled for release this Monday and I need to get this working.