VR Game, NavMeshAgent plays fall anim instead of the run anim? Newbie Coder

Hi,

I was following MathewHallberg's VR Shooter tutorial:

Original code: http://wirebeings.com/how-to-make-virtual-reality-game.html

Following the video I had this issue first: `NavMeshAgent' could not be found. Are you missing `UnityEngine.AI' using directive? Which I fixed this by using UnityEngine.AI;
Now when I press play the navmeshagent just plays the fall animation and literally falls through the floor (both have colliders)

All I changed with the script is 1- UnityEngine.AI; 2- Changed name from zombiescript to enemyscript 3- changed term zombie to enemy in the script as that is the name of my navmeshagent.
I am using Unity 2018.1.0f2

I would really appreciate some help with this and if someone could provide a good read on coding specific to unity that would also be great.

This is the Enemyscript:

Code (CSharp):

1. using UnityEngine;
2. using System.Collections;
3. using UnityEngine.AI;
4.  
5. public class EnemyScript : MonoBehaviour
6. {
7.     //declare the transform of our goal (where the navmesh agent will move towards) and our navmesh agent (in this case our zombie)
8.     private Transform goal;
9.     private NavMeshAgent agent;
10.  
11.     // Use this for initialization
12.     void Start()
13.     {
14.  
15.         //create references
16.         goal = Camera.main.transform;
17.         agent = GetComponent<NavMeshAgent>();
18.         //set the navmesh agent's desination equal to the main camera's position (our first person character)
19.         agent.destination = goal.position;
20.         //start the walking animation
21.         GetComponent<Animation>().Play("Anim_Run");
22.     }
23.  
24.  
25.     //for this to work both need colliders, one must have rigid body, and the zombie must have is trigger checked.
26.     void OnTriggerEnter(Collider col)
27.     {
28.         //first disable the zombie's collider so multiple collisions cannot occur
29.         GetComponent<CapsuleCollider>().enabled = false;
30.         //destroy the bullet
31.         Destroy(col.gameObject);
32.         //stop the zombie from moving forward by setting its destination to it's current position
33.         agent.destination = gameObject.transform.position;
34.         //stop the walking animation and play the falling back animation
35.         GetComponent<Animation>().Stop();
36.         GetComponent<Animation>().Play("Anim_Death");
37.         //destroy this zombie in six seconds.
38.         Destroy(gameObject, 6);
39.         //instantiate a new zombie
40.         GameObject Enemy = Instantiate(Resources.Load("Enemy", typeof(GameObject))) as GameObject;
41.  
42.         //set the coordinates for a new vector 3
43.         float randomX = UnityEngine.Random.Range(-2f, 11.5f);
44.         float constantY = 0f;
45.         float randomZ = UnityEngine.Random.Range(12f, 21f);
46.         //set the zombies position equal to these new coordinates
47.         Enemy.transform.position = new Vector3(randomX, constantY, randomZ);
48.  
49.         //if the zombie gets positioned less than or equal to 3 scene units away from the camera we won't be able to shoot it
50.         //so keep repositioning the zombie until it is greater than 3 scene units away.
51.         while (Vector3.Distance(Enemy.transform.position, Camera.main.transform.position) <= 3)
52.         {
53.  
54.             randomX = UnityEngine.Random.Range(-12f, 12f);
55.             randomZ = UnityEngine.Random.Range(-13f, 13f);
56.  
57.             Enemy.transform.position = new Vector3(randomX, constantY, randomZ);
58.         }
59.  
60.     }
61.  
62. }