Hey @Lars,
There is a new update for Facebook Events. Facebook Events is now at version 4.2, as of this morning.
All of our plugins were updated to 4.2 today: The Events Calendar, Events Calendar Pro, Facebook Events, everything….
So, I would recommend updating everything you can. If you do not get a notice to update to 4.2 in your wp-admin, then this may be happening for a number of reasons. Make sure you have entered your Facebook Events license key…if you have made sure this was set and saved, and no update notice arrives, then we can do further troubleshooting from there—but, in the meantime, I would recommend updating manually just to get your site in top shape. You can do that by getting the plugin files directly any time at http://theeventscalendar.com/my-account/downloads
Thank you,
George