Pieter,
Sorry to hear you ran into issues. We haven't heard of this problem often, and it seems like a bug in Joomla that crops up every once in a while under very specific (and unknown) circumstances. Was the specific error something like "Error Building Admin Menus"?
If so, usually the JFBConnect menu item is still visible under the Components drop down. The sub-menus (like Configuration, Social, Profiles, etc) simply don't show up. Those are all available by going to the main JFBConnect menu item and then clicking into those sub-menus available at the top.
Sometimes, simply uninstalling and re-installing the component will re-build the menus properly. Uninstalling shouldn't cause any issues as JFBConnect will retain its settings if you do. If that doesn't work though, you'll need to run some SQL queries on your database to fix one of the tables. Basically, the menus have been created, but they have an improper ID set with them (usually '0') that simply needs to be updated appropriately.
Let us know if the above helps clarify or fix things up, and we'll do what we can to help get things going.
Thanks,
Alex