Use of an AI script, and having it NOT go through walls using a character controller

This questions arises from a different question regarding an AI script and is a continuation of the topic. While functional, has the enemy its used on go through walls. This is problematic on several levels, unless the enemy is a ghost.

A fellow used suggested rescripting the script without using transform.translate, and instead use character controllers and their functions. here is what it looks like so far...

     var distance = 0.00;
     var target : Transform;    
     var lookAtDistance = 15.0;
     var attackRange = 10.0;
     var moveSpeed = 5.0;
     var damping = 6.0;
     var controller : CharacterController;
     var forward : Vector3;
     var curSpeed : float = 1;
 
 
     function Start(){
     
     controller = GetComponent(CharacterController);
     forward = transform.TransformDirection(Vector3.forward);
     }
 
     function Update () 
     {
     distance = Vector3.Distance(target.position, transform.position);
  
     if(distance < lookAtDistance)
     {
 
 
     lookAt ();
     }   
     if(distance > lookAtDistance)
     {
 
     }
     if(distance < attackRange)
     {
     NextPos = target.position;
     attack ();
     }
 }
  
  
 function lookAt ()
 {
 var rotation = Quaternion.LookRotation(target.position - transform.position);
 transform.rotation = Quaternion.Slerp(transform.rotation, rotation, Time.deltaTime * damping);
 }
  
 function attack ()
 {
     controller.Move(forward * curSpeed);
 }
  
 

It still does not work, and I'm seeking assistance with it, I'm not asking for someone to write the script for me as some people dislike, I'm looking for what parts of the script are wrong and how to fix it. The problem now is that it does not move.