Your description of the display hierarchy is quite confusing. Your stage is an instance called player? You put the enemy inside the player? Give the full display paths of the objects in question, such as:
main timeline -> player
main timeline -> mc -> enemy
Without a clear understanding of the hierarchy it's impossible to use the parent property effectively.
Also note that stage and root are different. The root is inside the stage. The main timeline in Flash is compiled as the root, so refer to your main timeline as root, not stage.
You can use this method to determine the exact display object path of any display object:
ActionScript Code:
function getDisplayPath(object:DisplayObject):String {
var a:Array = [];
while(object){
a.unshift(object.name || object.toString());
object = object.parent;
}
return a.join(".");
}