on trigger, button activate change level

hello how do i make this code work, what im trying to do is make it on the trigger the charter has to press Input button "grab" to make the level change.

//Enter poor house 1
function OnTriggerEnter (other : Collider) 
{
     if (Input.GetButtonDown("grab"))
     {
         Application.LoadLevel ("poor house 1");
     }
}

http://answers.unity3d.com/questions/12824/triggering-a-door-to-open