I made a little mistake in the skipForward code.
It should be...
Code:
skipForward.onPress = function(){
  curPos = mySound.position / 1000;
  newPos = math.Min ( (mySound.duration -1)/ 1000, curPos + 10);
  mySound.stop();
  mySound.start( newPos );
}
to start 1/1000sec before the end when the end is reached. Otherwise it won't function properly.