I am having the same problem with Google Maps not appearing in the event view. As it happens, I have a dev site that was functioning perfectly and includes all the plugins in use on the live site. Because I had not been to the dev site recently many of the plugins were out of date, including Events Calendar Pro. WordPress had been updated to 4.0 automatically, but the Maps function was working fine. I updated each plugin one-by-one and kept refreshing the page. After all but Events Calendar had been updated, Google Maps was still functioning perfectly. I updated the Events Calendar plugins, hit refresh, and the maps window went blank.
I tried adding the code to the functions.php file, but it had no effect, disappointingly. Dev site URL: http://dev.diocese-oregon.org/