When you enter the 'New Game' menu but have already something else bound to the 61357 TCP port, GAE bails out with an error:
Socket Error in : bind() [Error code: 98]
Address already in use
While the 'New Game' menu can be used to start a network game, it does not do so by default (the default seems to be a local human vs AI game), so it should not expect to be able to bind to this port. In fact, it should not do any socket operations until the user actually opens a network player slot.