The error message is still there....
   
   
            public void lobsterPowerUp()
{
    Crab crab = (Crab) getWorld().getObjects(Crab.class).get(0);
    if (getWorld().getObjects(Lobster.class).isEmpty()) return;
    Lobster lobster = (Lobster) getWorld().getObjects(Lobster.class).get(0);
    
    if (crab != null && crab.dp2Powered())  
    {  
        turnTowards(lobster.getX(), lobster.getY());  
        move(3);  
        //if (getWorld().getObjects(Lobster.class).isEmpty()) return;
    }  
}if (getWorld().getObjects(Crab.class).isEmpty()) return;