The new SCLogin module, v3.0 and higher, is only meant to work with JFBConnect v5.0 or higher. The v4.2 and v4.3 releases are almost a year old now, and things have changes substantially since then. The new SCLogin module has a very improved interface and modal popup options. JFBConnect support Google+ authentication, Open Graph Actions, and has a whole new profile system for integration with 3rd parties.
If you stay with JFBConnect v4.x, you'll need to downgrade the SCLogin module back to the 2.x release that came with that version. If you need a copy of the older version of SCLogin, we can gladly send it to you. Otherwise, we'd highly recommend upgrading to JFBConnect v5.1 and take advantage of all the new features available.
Thanks,
Alex