Locking z access causes a stuck character

I have a script in which I am attempting to lock a 3D character so that movement is only possible in the x any y axis (only x is really important though). I am using a character controller so the usually method using a configurable joint doesn't seem to work.

I made the following script, but when I use any of the commented out lines at the bottom, it just locks the character in position on all axes.

Been pulling my hair out over this for a while. Any help would be appreciated.

 #pragma strict
 
 var moveSpeed :float = 2;
 var rotateSpeed :float = 30;
 var facing: float = 1;
 var zaxis: float = 0;
 
 function Start () {
     zaxis = transform.position.z;
 }
 
 function Update () {
     
     var controller : CharacterController = GetComponent(CharacterController);
     var king = GameObject.Find("SpartanKing"); // Get the model
     var h = Input.GetAxis("Horizontal");
     
     var forward : Vector3 = transform.TransformDirection(Vector3.forward);
     controller.SimpleMove(forward * moveSpeed * h); //possibly remove facing when you fix the camera
     
     //Animate
     if    (Input.GetKeyDown("space"))
     {
         king.animation.Play("attack");
     }
     else
     {
         if (h == 0) // Standing Still case case
         {
             king.animation.Play("idle");
         }
         else // Moving cases
         {
             if (h != facing) // turn around case
             {
                 facing = h;
                 if (h < 0)
                     king.transform.eulerAngles = Vector3(0,270,0);
                 else
                     king.transform.eulerAngles = Vector3(0,90,0);
             }
             
             king.animation.Play("run");                
         }
     }
     // Attempted solutions.
     
     //controller.transform.position.z = zaxis;
     //transform.position.z = zaxis;
     //transform.position.z = 1000;
     //transform.position = new Vector3(transform.position.x, transform.position.y, zaxis);
 
 }