World problem

import greenfoot.*;

public class MyWorld extends World
{
    public MyWorld()
    {
        super(1500, 730, 1); 
        Dolphin dolphin = new Dolphin(label);
        Ground ground = new Ground();
        Label label = new Label("C O U N T : 0");
        
        addObject(dolphin,/**x*/64, /**y*/689);
        addObject(ground, 538, 722);    
        addObject(label, 150, 150);
    }
}