Crate not disappearing...

So I am watching a tutorial by Jimmy Vegas, and I am on the ammo pickup video. When I walk into the crate, my ammo increases, but the crate doesn’t hide, allowing form unlimited ammo. Also, if possible, can someone help me set a max ammo carry of 30? Can someone please help? (script)

function OnTriggerEnter (col : Collider) {
	GlobalAmmo.CurrentAmmo += 10; 
	this.GameObject.SetActive(false); 

}

Replace this:

this.GameObject.SetActive(false); 

with this:

this.gameObject.SetActive(false); 

Notice the capitalization