Object deletes when a script is added.

I am trying to add a script to an empty game object but when i add it the object deletes. How can i fix this? Here is my code:

using UnityEngine; using System.Collections; using UnityEngine.UI;

public class GM : MonoBehaviour {

 public int lives = 3;
 public int bricks = 20;
 public float resetDelay = 1f;
 public Text livesText;
 public GameObject gameOver;
 public GameObject youWon;
 public GameObject bricksPrefab;
 public GameObject paddle;
 public GameObject deathParticles;
 public static GM instance = null;

 private GameObject clonePaddle;

 // Use this for initialization
 void Awake () 
 {
     if (instance == null)
         instance = this;
     else if (instance != this)
         Destroy (gameObject);

     Setup();
 
 }

 public void Setup()
 {
     clonePaddle = Instantiate(paddle, transform.position, Quaternion.identity) as GameObject;
     Instantiate(bricksPrefab, transform.position, Quaternion.identity);
 }

 void CheckGameOver()
 {
     if (bricks < 1)
     {
         youWon.SetActive(true);
         Time.timeScale = .25f;
         Invoke ("Reset", resetDelay);
     }

     if (lives < 1)
     {
         gameOver.SetActive(true);
         Time.timeScale = .25f;
         Invoke ("Reset", resetDelay);
     }

 }

 void Reset()
 {
     Time.timeScale = 1f;
     Application.LoadLevel(Application.loadedLevel);
 }
 
 public void LoseLife()
 {
     lives--;
     livesText.text = "Lives: " + lives;
     Instantiate(deathParticles, clonePaddle.transform.position, Quaternion.identity);
     Destroy(clonePaddle);
     Invoke ("SetupPaddle", resetDelay);
     CheckGameOver();
 }

 void SetupPaddle()
 {
     clonePaddle = Instantiate(paddle, transform.position, Quaternion.identity) as GameObject;
 }

 public void DestroyBrick()
 {
     bricks--;
     CheckGameOver();
 }

}