Yes, you'll need to use the v6.1 release of JFBConnect to use SCLogin v4.1. The next v4.1.1 release will have a proper check to prevent installation whenever the proper version of JFBConnect is not found.
If you want to downgrade back to the v4.0.6 release, you can download that version
here
.
Sorry for the trouble, and I hope the above helps get you going,
Alex