Your spawn
method is a handler for the addedToStage
event so it expects the event object as a parameter:
function spawn(event:Event)
{
removeEventListener(Event.ADDED_TO_STAGE, spawn);
getMap();
this.stage.addEventListener(KeyboardEvent.KEY_DOWN, kPress);
this.stage.addEventListener(KeyboardEvent.KEY_UP, kReleased);
this.addEventListener(Event.ENTER_FRAME, loop);
}