@Tookman
representing the shark you added as the location
par = new shark();
par.x = 300;
par.y = 100;
then in the shark class you use the location of the clip
this.graphics.drawRect(this.x, this.y, 10, 10);
which makes it
graphics.drawRect(300, 100, 10, 10);
if your screen width is only 550 you would never see the rectangle as it is placed 300 pixels in on the stage and placed 300 pixels out on the sprite itself. If you wanted a 10x10 square it would be like this
graphics.drawRect(0, 0, 10, 10);
if you wanted a centered square, you could offset the size of the square to half the width.
graphics.drawRect(-5, -5, 5, 5);
this would make a 10x10 square that is centered directly where the child is added.
About your code on the previous page
stage.addEventListener(Event.ENTER_FRAME, keys);
stage.addEventListener(KeyboardEvent.KEY_DOWN, keysdown);
stage.addEventListener(KeyboardEvent.KEY_UP, keysup);
stage.addEventListener(Event.ENTER_FRAME, keys);
addEventListener(Event.ENTER_FRAME, gameLoop);
remove those listeners there is no function associated with them