Hi Rudi,
It seems your home page is broken; there might be a conflict somewhere.
I know your Events Calendar plugins are up-to-date, but can you make sure all your other plugins are also updated? The same with your theme — be sure you have the latest version installed.
Then, could you deactivate all your plugins, except The Events Calendar, Events Calendar PRO, Fusion Builder and Fusion Core? Is it still broken that way? You may want to read our documentation about testing for conflicts before doing those tests.
Please let me know how it goes,
Jeremy