Hi everyone. I have a powerup in my game called crate. When the player collides with it I'm trying to run a function called MachineGun() in my FireScript that increases the bullet fireFreq. When my player collides with the powerup I'm getting a NullReferenceException and I don't know why.

GameController.js

function OnTriggerEnter(col:Collider){
            if(col.gameObject.tag == "Player" && canPickup){
            canPickup = false;
                GameObject.Find("PlayerPrefab").GetComponent(FireScript).MachineGun(); //error occurs here. My player is called PlayerPrefab, the FireScript is attached to the prefab, and the script contains a MachineGun() 
               var cloneCrateSound = Instantiate(crateCollectionSnd, transform.position, transform.rotation);
               var cloneArmsCollected = Instantiate(armsCollected, transform.position, Quaternion.Euler(Vector3(0,180,0)));

               renderer.enabled = false;
               yield WaitForSeconds(2);
               Destroy(cloneCrateSound);
               Destroy(cloneArmsCollected);
               Destroy(gameObject);
            ...
            }

In FireScript.js

function MachineGun(){
    gunType = 1;
    bulletTimer = 10;
}