I am using Joomla 1.5.25, CB 1.8 (updated it yesterday). It has worked before.
The issue is not the registration process. The issue is returning to the login page and trying to log without having the "Remember Me" box checked. It just gets you back to the same page without login you in.
I am having a similar issue. I am running Joomla 2.5.8 and CB 1.9 as well as CB Login, CB online, and CB Workflows, All say v 1.9. Login works great as long as Remember me is checked...