How to Instantiate Prefab as Child of Player OnTriggerEnter

Hello, I am a Unity beginner and have been searching for a while without success. I have a CharacterController named "Player" that I would like to have run into a trigger GameObject(which I place my JavaScript onto). I would then like for OnTriggerEnter to instantiate a prefab (this will be the Flame prefab in Unity_StandardAssets_Particles_Fire). I can get this to work, but I want the prefab to then become a child of the "Player" so that it stays on my character. I have tried the following code which successfully instantiates the prefab OnTriggerEnter (it just stays with my trigger GameObject and does not become a child of my "Player". I am getting an error:

"InvalidCastException: Cannot cast from source type to destination type."

My Code:

var instantiation : Transform; var player: Transform;

  function OnTriggerEnter (other : Collider) 
  {
      if(other.gameObject.name=="Player"){
       
    var newPrefab : Transform; 
    newPrefab = Instantiate (instantiation, transform.position, transform.rotation);
    newPrefab.parent = player; 
    newPrefab.localRotation = Quaternion.identity; 
    }
  }

Thanks for any Help!