The joomla user plugin must execute before the jfbconnectuser

Go to "Extensions->Plugin Manager" in the admin area. Then, scroll down to the User plugin area. Ensure that the 'ordering' number next to the JFBConnect User plugin is higher than the Joomla User plugin. They should not both be the same either.

Hope this helps clarify. Let us know if you have any other questions.

The JFBC User plugin should be ordered AFTER the Joomla user plugin, not before. That should fix your problem.

Glad you figured it out. Just so you know (general Joomla background), there's usually 2 reasons you can't reorder from the main page:
1) Someone is already editing a plugin, which checks it out. This prevents you from re-ordering other plugins because it can't 'change' the checked out plugin. To fix, you can either go to Tools->Global Checkin.
Alternatively, you can try to use the filter to show just the plugins in the group you want to re-order. While that won't fix a 'checked out' plugin, if the one that's checked out isn't in the group shown, it won't prevent the ordering of the shown ones.
2) A bug in Joomla is that if there are two plugins ordered the same (with an ordering of 1 for instance), the up and down arrows don't work for those plugins. In this case, you can manually type the number in and hit the save icon at the top of the column.

I know you said you got it fixed, but hopefully the above gives you some more insight into how Joomla works and some nice tricks to prevent you from pulling your hair out again!

Good luck, and let us know if there's anything else we can help with!