Sidescroller Turning

I've edited this WoW Camera Script to fit my character properly, but when he turns around to run left, he turns around, but he moves to the right still. Could anyone lend a hand? Here's the script.

// Movement Variables
private var jumpSpeed:float = 9.0; 
private var gravity:float = 100.0; 
private var rotateSpeed:float = 250.0; 
private var grounded:boolean = false; 
private var moveDirection:Vector3 = Vector3.zero; 
private var isWalking:boolean = true; 
private var moveStatus:String = "idle"; 
private var xSpeed = 250.0; 
private var ySpeed = 120.0; 
private var yMinLimit = -40; 
private var yMaxLimit = 80; 
private var x = 0.0; 
private var y = 0.0; 

static var walkSpeed:float = 15.0; 
static var isRunning:boolean = false;
static var isMoving:boolean = false;

function Start ()
{
   // Set all animations to loop
   animation.wrapMode = WrapMode.Loop;
   animation.Stop();
}

// -------------------------------------------------------------------------------------------------------------
// ----------------------------------------------------------- UPDATE ---------------------------------------
// -------------------------------------------------------------------------------------------------------------

function Update () {
   if(grounded) { 
        moveDirection = new Vector3(0,0,Input.GetAxis("Horizontal")); 
        if(Input.GetAxis("Horizontal")) { 
            moveDirection *= .7; 
            transform.LookAt(transform.position + moveDirection); 

        } 
        moveDirection = transform.TransformDirection(moveDirection); 
        moveDirection *= walkSpeed;
        moveStatus = "idle"; 
        if(moveDirection != Vector3.zero) {
            animation.CrossFade("run",0.2);
            isMoving = true;
        } else {
            isMoving = false;
            animation.CrossFade("Take 001",0.2);
        }
    }                           
    //////////

    if(Input.GetKey("q")) {
        isRunning = true;
        walkSpeed = 50;
    }else{
        isRunning = false;
        walkSpeed = 30;
    }
    //////////

    moveDirection.y -= gravity * Time.deltaTime; 
    var controller:CharacterController = GetComponent(CharacterController); 
    var flags = controller.Move(moveDirection * Time.deltaTime); 
    grounded = (flags & CollisionFlags.Below) != 0; 
    };
    static function ClampAngle (angle : float, min : float, max : float) { 
   if (angle < -360) 
      angle += 360; 
   if (angle > 360) 
      angle -= 360; 
   return Mathf.Clamp (angle, min, max); 
} 

@script RequireComponent(CharacterController)

I guess your problem is that controller.Move expects a velocity in local coordinates and you transformed it to world space earlier with transform.TransformDirection.