Upgrading from Form Tools 2
Versions 2.x of this module support Form Tools 3. Along with that update, this module now uses the latest version of Google Maps which requires supplying a Google Maps key from Google. To do this, go to this page. That will lead you through the steps to acquire an API key.
When you have set it up with Google, log in as the Form Tools administrator and go to Modules » Google Maps Field. There, enter your API key and save.
Done! Now your Google Maps fields will work as before.