I was using this plugin successfully on a development site, but when I transferred it to a live server (same host, different account), I began getting this error which sounds to be common:
The Google Maps API server rejected your request. The "sensor" parameter specified in the request must be set to either "true" or "false"."
I was also unable to update or save any settings through the plugins admin area in WP-Admin.
Hopefully this will help anyone else having this problem.