First, I'm glad you updated. Joomla 2.5.9 was very old.
As for the issue when the SCLogin module is published, can you tell me that exact error? I'm assuming it's different from the one you were getting with the JFBCSystem plugin. Knowing the exact error will help narrow things down.
Also, if you aren't using 6.2.2 yet (released on Friday), please upgrade to that. A few kinks have been worked out since the 6.2.0 release early last week.
Thanks,
Alex