When page loads i get the message as javascript alert:
Google has disabled use of the Maps API for this application. See the Terms of Service for more information: ht
My web application had this same error occur, and we fixed it by updating our link to the Google Maps API file.
Previously we were using a downloaded version of the Maps API file located at http://maps.googleapis.com/maps/api/js?key=YOUR_API_KEY&sensor=SET_TO_TRUE_OR_FALSE.
When we instead used the direct link, this particular error went away.
Edit: Even if you're directly linking to Google's js file, make sure your application isn't using an older locally cached version.
Not working version: