Hi Moe,
just used the API the first time today and ran into the same issue. Since the rest of the API seems to be very well done, I am assuming this is just a minor oversight and will be properly fixed at some point by the project staff.
I was able to fix it by just creating the interface com.codeminders.ardrone.
version.DroneVersionReader . In fact, I used eclipse's option to resolve the error by having it create the interface for me. Also, in DroneFTPVersionReader, you'll either have to remove the @Override directive or create the overridden method stub in DroneVersionReader.
Also, I noticed that the UDP Port for AT commands is wrong. It is set to 5559, but on AR.Drone 2.0, firmware 2.2.3 it seems to be 5556. This problem prevented me from connecting to the drone using ControlTower.I fixed it by changing the port in the ARDrone class.
Cheers,
Bastian