Hello Gregory,
When you create the GoogleMapsLayer, you need to set a privatekey, that is your Google Maps APIs key, like the code below, API Key is "ABQIAAAA1KPQi4YfHGdBrxrD7xfk3BShg55qzDjUncDQtZWMkgWc-6jGwhTE2_EhbB-MTW6vtSxa--SpoABjPA"
GoogleMapsLayer googleLayer = new GoogleMapsLayer("c:\\cache\\", "GoogleMapLayer1", "ABQIAAAA1KPQi4YfHGdBrxrD7xfk3BShg55qzDjUncDQtZWMkgWc-6jGwhTE2_EhbB-MTW6vtSxa--SpoABjPA");
But this key is not working now, as for the Google Maps APIs key, I suggest that you refer to the web page below which has clarified how to register the key and make it valid for that domain, its subdomains, all URLs on hosts in those domains.
code.google.com/apis/maps/faq.html#keysystem
Regards,
Gary