Follow AI which avoides obstacles

Hey, so I have this AI script where if you get close to the enemy he will start chasing you. The first part which is just simply checking if you're close and chasing you works perfectly. It looks like this.

 var player : Transform; // the Object the player is controlling
 var spawnOrgin : Vector3; // this will be the bottom right corner of a square we will use as the spawn area
 var maximum : Vector3; // max distance in the x, y, and z direction the enemy can spawn
 var spawnRate : float; // how often the enemy will respawn
 var distanceToPlayer : float; // how close the enemy has to be to the player to play music
 var nearPlayer : boolean = false; // use this to stop the teleporting if near the player
 
 var target : Transform; //the enemy's target
 var moveSpeed = 3; //move speed
 var rotationSpeed = 3; //speed of turning
 var myTransform : Transform; //current transform data of this enemy
 var chasing : boolean = false;
 
 private var nextTeleport : float = 0.0f; // will keep track of when we to teleport next
 
 function Awake()
     {
         myTransform = transform; //cache transform data for easy access/preformance
     }
      
 function Start ()
     {
         target = GameObject.FindWithTag("Player").transform; //target the player
         nextTeleport = spawnRate;
     }
      
 function Update ()
 {
     transform.position.y=-6.357718f;
     
     if (!nearPlayer) // only teleport if we are not close to the player
     {
         if (Time.time > nextTeleport) // only teleport if enough time has passed
         {
             transform.position = Vector3( Random.Range(spawnOrgin.x, maximum.x), Random.Range(spawnOrgin.y, maximum.y), Random.Range(spawnOrgin.z, maximum.z) ); // teleport
             nextTeleport += spawnRate; // update the next time to teleport
         }
     }
     if (Vector3.Distance(transform.position, player.position) <= distanceToPlayer)
     {
         if (audio && audio.clip && !audio.isPlaying && renderer.isVisible) // play the audio if it isn't playing
         audio.Play();
         nearPlayer = true;
         chaseIsOn();
     }
     else
     {
         if (audio)
         audio.Stop();
         nearPlayer = false;
     }
     if (chasing)
     {
          myTransform.rotation = Quaternion.Slerp(myTransform.rotation,
 Quaternion.LookRotation(target.position - myTransform.position), rotationSpeed*Time.deltaTime);
  
 //move towards the player
 myTransform.position += myTransform.forward * moveSpeed * Time.deltaTime;
     }
 
 }
 
 function chaseIsOn()
 {
     Debug.Log("THE CHASE IS ON");
     chasing = true;
 }
 

But now I'm trying to add obstacle avoidance which is not working so well. I tried adding this simple one from his video. It just doesn't work at all. It gives me errors. Is there any simple way you cans see to add obstacle avoidance into the script. If you see any please do say! thanks.