I have downloaded and installed Google Map Selection Field module, but couldn't make it work.

I have add the following line in the _config.php
EditableGoogleMapSelectableField::$api_key = 'ABQIAAAAdc7-XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX';

and inside one of the page type in the cms, I have added the following:

$fields->addFieldToTab('Root.Content.GoogleMap', new GoogleMapSelectableField('MyMap'));

The tab and field show up correctly, however every time I fill in the address and click 'go' button the page go blank, the url shows that its calling the EditForm function. what should I do to get this field to work properly?

Thank you for taking your time to read this.