Unity Networking Client NullReferenceException Error

In essence I am creating a game that involves a shooting mechanism contained in script PlayerShoot that is attached to a player prefab and a damage registering script damageDealer attached to a bullet. My problem is whenever the host player fires and hits a non host client player my code works and returns a Player 2 has been shot; however, when a client fires at a host it returns the following error

NullReferenceException: Object reference not set to an instance of an object at damageDealer.OnCollisionEnter (UnityEngine.Collision collision) [0x00045] in C:\Users\thebr\MultiShooter\Assets\Scripts\damageDealer.cs:41

PlayerShoot:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using UnityEngine.Networking;
 
 public class PlayerShoot : NetworkBehaviour {
 
   public PlayerWeapons weapon;
 
   [SerializeField]
   private Camera cam;
 
   public GameObject bulletPrefab;
   public Transform bulletSpawn;
 
   public bool hitTarget = false;
   public string targetHit;
 
   void Start ()
   {
     if (cam == null)
     {
       Debug.LogError("No camera referenced: PlayerShoot");
       this.enabled = false;
     }
   }
 
 
   void Update ()
     {
       if (Input.GetMouseButtonDown(0))
       {
         CmdFire();
       }
 
     if (hitTarget == true)
     {
       CmdPlayerShot(targetHit);
       hitTarget = false;
     }
 
   }
 
   [Command]
   void CmdFire()
   {
     if (weapon.name == "Phase Rifle")
     {
       var bullet = (GameObject)Instantiate(
       bulletPrefab,
       bulletSpawn.position,
       bulletSpawn.rotation);
 
       bullet.GetComponent<Rigidbody>().velocity = bullet.transform.forward * 60;
       bullet.tag = "PhaseRifleBullet";
       bullet.transform.GetComponent<damageDealer>().parentID = gameObject.name;
 
       NetworkServer.Spawn(bullet);
 
       Destroy(bullet, weapon.rangeTime);
 
     }
     else
     {
       Debug.LogError("You have no weapon equipped");
     }
 
     
   }
 
   [Command]
   void CmdPlayerShot(string _playerID)
   {
     Debug.Log(_playerID + "has been shot");
   }
 }

damageDealer

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using UnityEngine.Networking;
 
 public class damageDealer : NetworkBehaviour
 {
   [SerializeField]
   private int damage = 0;
 
   public string parentID;
   
 
   // Use this for initialization
   void Start()
   {
     if (gameObject.tag == "PhaseRifleBullet")
     {
       damage = 5;
       
       
     }
   }
 
   // Update is called once per frame
   void Update()
   {
 
   }
 
   
   void OnCollisionEnter(Collision collision)
   {
 
     if (collision.gameObject.layer == 10)
     {
       
       var target = collision.gameObject;
       target.transform.GetComponent<PlayerController>().health -= damage;
       GameObject origin = GameObject.Find(parentID);

       //The error is triggered by the following two lines
       origin.transform.GetComponent<PlayerShoot>().hitTarget = true;
       origin.transform.GetComponent<PlayerShoot>().targetHit = target.name;
 
     }
   }
 
  
 }