I have this code, and it works for the most part. the only problem is that it only updates its position when i'm turning the character or turning the camera. if i make the character walk forward or backwards, the camera will maintain it's current position until i force it to rotate, then it will snap back to the character. Some help, please?

var target : Transform;
var zoom_distance = 5.0;
var zoom_distanceMin = 5.0;
var zoom_distanceMax = 20.0;
var camera_height = 1.0;

var xSpeed = 250.0;
var ySpeed = 120.0;

var yMinLimit = -75;
var yMaxLimit = 75;

var positionDamping = 2.0;

private var x = 0.0;
private var y = 0.0;

private var zoom = 0.0;

private var last_rotation : Quaternion;

private var doing_smoothfollow : boolean = false;

function Start () {
    var angles = transform.eulerAngles;
    x = angles.y;
    y = angles.x;

    // Make the rigid body not change rotation
    if (rigidbody)
       rigidbody.freezeRotation = true;
}

function LateUpdate () {
    if (target) {
       // Scrollwheel to set camera distance

      zoom_distance = Mathf.Clamp(zoom_distance - Input.GetAxis("Mouse ScrollWheel")*2, zoom_distanceMin, zoom_distanceMax);

       if(Input.GetButtonDown("Fire2")){
       // The Unity script inverses the x and y.

       // Also, start adding the mouse rotation to the current transform Euler Angles
       x = transform.eulerAngles.y;
       y = ClampAngle(transform.eulerAngles.x, yMinLimit, yMaxLimit);
       }

        if(Input.GetAxis("Fire2")){

       // Add mouse values to rotation, based on the previous camera rotation

        x += Input.GetAxis("Mouse X") * xSpeed * 0.02;
        y -= Input.GetAxis("Mouse Y") * ySpeed * 0.02;

       // Clamp the y so weird things don't happen

      y = ClampAngle(y, yMinLimit, yMaxLimit);

        var rotation = Quaternion.Euler(y, x, 0);
        var position = rotation * Vector3(0.0, camera_height, -zoom_distance) + target.position;
        transform.position = position;
        transform.rotation = rotation;
        last_rotation = rotation;
        }

    //Smooth follow if turning or tilting or the camera hasn't reached it's last rotation (before it was moved)

    else if(Input.GetAxis("Horizontal") || Input.GetAxis("NoseThrust") || doing_smoothfollow){

    //TODO: Implement doing_smoothfollow to let camera settle down behind ship

    wantedRotationAngle = Quaternion.Angle(transform.rotation, target.rotation);

    // Quaternion smooth follow

    transform.rotation = Quaternion.Slerp(transform.rotation, target.rotation, positionDamping * Time.deltaTime);

    transform.position = transform.rotation * Vector3(0.0, camera_height, -zoom_distance) + target.position;

    last_rotation = transform.rotation;
    }

    else {
       //Follow player even when not pressing 3rd mouse button

       transform.position = last_rotation * Vector3(0.0, camera_height, -zoom_distance) + target.position;

       transform.rotation = last_rotation;
    }

    }

}
static function ClampAngle (angle : float, min : float, max : float) {

    if (angle < -360)
       angle += 360;
    if (angle > 360)
       angle -= 360;

       // Hacked to get it working with the Euler angles. Could be better I guess...
    if(angle > 360+min)

       //angle = 180 -angle;
       return angle;
    if(angle > 180)
       angle = -angle;
    return Mathf.Clamp (angle, min, max);

}