If you want your code to work across multiple domains when using Google Maps you will need to dynamically change your Google Maps key based on request. Google requires you have a unique key for each host that makes calls into Google.

I solved this by placing a few statements in my application.cfc onrequest function.

The code checks the cgi.http_host and then sets the correct key value.

I created the all the keys at http://code.google.com/apis/maps/signup.html

If you just have one host you can alternatively set the key inside the administrator.