Google Maps plugin just shows a rotating icon when I click "Add Map"

Hello Support.

I have a localhost sandbox installation of Events+ and Google Maps plugins.

When I click on the small "Add Map" button on the Events Edit screen (under Event Details) the window pops up and the rotating icon keeps going round and round but no map shows up.

The actual map shows up on the "Events" page just fine, but I cannot customize it via this pop up window.

Can you help??

Thanx in advance.