Did you talk to the childs parents after she threw clumps of dirt at your dog? In YOUR back yard? It might help. You should keep a very close eye on the dog though. I don't get that she is scared
of your dog when it is harmless. Who knowes? Maby she heard a news report with somthing with a Mastiff in it, if you know what I mean. I don't know what to say, though, really about that!