NullReferenceException...

I have been following a tutorial series on youtube and I so far I have done everything correct. Until now, I have this error…

NullReferenceException: Object reference not set to an instance of an object
Boo.Lang.Runtime.RuntimeServices.InvokeBinaryOperator (System.String operatorName, System.Object lhs, System.Object rhs)
CollisionDetectionSphereScript.Update () (at Assets/CollisionDetectionSphereScript.js:10)

I sort of understand this means that the script cannot find the item you have selected, or if you have selected one at all.

Here is my code:

var floatAbove : float = 0.1;
var playerCapsuleTransform : Transform;
@HideInInspector
var collisionDetected : boolean = false;

function Update () {

	transform.position.x = playerCapsuleTransform.position.x;
	transform.position.z = playerCapsuleTransform.position.z;
	transform.position.y = playerCapsuleTransform.position.y + ((playerCapsuleTransform.GetComponent(Collider).Height * playerCapsuleTransform.localScale.y) / 2 ) + (transform.localScale.y / 2) + floatAbove;

}

function OnCollisionStay (collision : Collision){

	if (collision.transform.tag == "Level Parts")
		collisionDetected = true;

}

function OnCollisionExit () {

	collisionDetected = false;

}

Now the error is pointing to line 10, but I included the entire script just in case it is a spelling error in another line. I have set the Player Capsule Transform in the Inspector but I still have this error. Please help me resolve this, Thank you.

Try this: playerCapsuleTransform.GetComponent(Collider).height