Need help with a checkpoint system

Hello. I was trying to make a checkpoint system. I wrote a script that should save your respawn place when you die.

private var dead = false;

function OnCollisionEnter(hit : Collision) { if(hit.gameObject.tag == "Terr") { dead = true; print ("NOOO!"); HealthControl.LIVES -= 1; }

if(hit.gameObject.tag == "checkpoint") { gameObject.Find("Respawn").transform.position = transform.position; Destroy(hit.gameObject); } }

function LateUpdate() { if(dead) { gameObject.Find("Main Camera").transform.position = Vector3(0,4,-10); transform.position = gameObject.Find("Respawn").transform.position; dead = false; } }

I dont understand what could be wrong to the script, but when I collide with my terrain I lose my main character and when I collide with my checkpoint and then with the terrain I get an error saying "null reference exeption". Whats wrong? Thank you for help, I hope you understand what I said.