Cant set default var value to script?

I have a transform var on my script. And I want to drag and drop something from the hierarchy to the var slot in the inspector, but I cant. It highlights as if it will drop, but it remains to say "none" also, I was able to do it once! I dropped a none-prefab object from the hierarchy to the Inspector, and now I cant do it. I've been trying on this for days and you can understand my frustration.

also, I can drop prefabs into the var slot, but only prefabs. Here's my script if that helps.

var LookAtThis : Transform;
var elaser : Transform;
var damp = 2;

function Update () {
if(Vector3.Distance(LookAtThis.position,transform.position) < 800){
var rotate = Quaternion.LookRotation(LookAtThis.position - transform.position);
transform.rotation = Quaternion.Slerp(transform.rotation, rotate,damp * Time.deltaTime);
transform.Translate(0,0, 10 * Time.deltaTime);

}

}
InvokeRepeating("fireAtPlayer",1,2);

function fireAtPlayer() {
if(Vector3.Distance(LookAtThis.position,transform.position) < 800){
Instantiate(elaser,transform.Find("espawnpoint").position,transform.rotation);
}
}

function OnCollisionEnter(hit : Collision) {
if(hit.gameObject.tag == ("Player"))
Debug.Log("Watch it!");
}

You can't drag game objects to scripts' default values. If you have an actual object with this script attached, you'll be able to drag game objects to its properties, otherwise you can only use prefabs.