i have the same issue & I don't know what cause the problem, either GPS poor locking (eventhough the GPS notification in status area says it's locking) or perhaps due to Google Maps is not running natively.

Here is the workaround, click on Latitude then Change your status -> fill nothing & just return to the main screen then My Location will appear in Menu (click it then wait a few moments for the bluedot adjusting to your actual location)