Damaging entities in radius

I am making a "Ground Pound" ability, and here is my code:

Code:

    @EventHandler
    public void onDamage(EntityDamageEvent d){
        if (d.getEntity() instanceof Player){
            Player faller = (Player) d.getEntity();
            if (d.getCause() == DamageCause.FALL){
                if (pounding.contains(faller.getName())){

                    pounding.remove(faller.getName());
                    d.setCancelled(true);

                    List<Entity> nearby =  ((Entity) d).getNearbyEntities(5,5,5);
                    for (Entity tmp: nearby)
                        if (tmp instanceof Damageable)
                            ((Damageable) tmp).damage(5);

                }
            }
        }
    }

When I use the abiltiy and hit the ground, I am supposed to deal 5 damage to all entities in a radius of 5 blocks. For some reason this isn't working.

There are no errors anywhere.

What have I forgotten to add?

 

You're casting the EntityDamageEvent to an Entity.
I think what you probably meant, was to get the damaged entity and get the entities near by.

Code:

d.getEntity()