inistiate at random point null reference

Hi it says that drop dosent exist even tho it does any ideas?

using UnityEngine;
using System.Collections;

public class Drops : MonoBehaviour {
	public Transform[] spawnPoints;
	Transform currentPoint;
	int index;
	public GameObject Drop;
	// Use this for initialization
	void Start()
	{

		index = Random.Range (0, spawnPoints.Length);
		currentPoint = spawnPoints[index];
		Instantiate (Drop, currentPoint.position, currentPoint.rotation);
	}
}

fixed it sorry i forgot to reasign the spawns as transforms they were still gameobjects… thanks for your help