BurgZergArcade tutorial 5 problem

I have been following the BurgZergArcade tutorials for making a Hack n Slash game. I'm on tutorial number 5, "Unity3d tutorial - Melee 1/3. I have copied all the code he wrote exactly, and there are no errors, but when I click the "F" key nothing happens. After some research I've noticed its a common problem, but i found no answers. Can someone please help me?

PlayerAttack.cs Code:

 using UnityEngine;
 using System.Collections;
 
 public class PlayerAttack : MonoBehaviour {
     public GameObject target;
 
     // Use this for initialization
     void Start () {
     
     }
     
     // Update is called once per frame
     void Update () {
         if(Input.GetKeyUp(KeyCode.F)) {
             Attack();
         }
     
     }
     
     private void Attack() {
         float distance = Vector3.Distance(target.transform.position, transform.position);
         
         Debug.Log (distance);
         
         if(distance < 2.5f) {
             EnemyHealth eh = (EnemyHealth)target.GetComponent("EnemyHealth");
             eh.AddjustCurrentHealth(-10);
         }
     }
 }