Hi,
You didn’t mention your phone model or Opera version, but it’s possible the maps javascript API isn’t supported on your device. Static maps work on everything but the API doesn’t.
You can try a simple test map here:
https://developers.google.com/maps/documentation/javascript/examples/map-simple
And Google’s FAQ lists supported devices:
https://developers.google.com/maps/faq
•IE 8.0+ (Windows) *
•Firefox 3.0+ (Windows, Mac OS X, Linux)
•Safari 4+ (Mac OS X, iOS)
•Chrome (Windows, Mac OS X, Linux)
•Android
•BlackBerry 6
•Dolfin 2.0+ (Samsung Bada)
* Internet Explorer’s Compatibility View is not supported.