Having issues with a smooth camera follow

First, if you past your code directly into the question (and format it using the 101/010 button), you are likely to get a much better response.

I made a quick pass through your code. It seems like an awfully complicated way to do smooth camera tracking with easing. There may be something specific you are getting out of it that I don't see. Here is an alternative script that tracks an object on the XY but leaves 'Z' alone. It attaches to the camera and expects the tracked object to be named "Player". But you can take the same logic and integrate into a 3-party script like yours:

 #pragma strict
 
 private var player : Transform;
 var deadZone = 0.15;
 var speed = 1.5;
 
 function Start () {
     player = GameObject.Find("Player").transform;
 }
 
 function Update () {
     var v3 = player.position;
     v3.z = transform.position.z;
     if (Vector3.Distance(v3, player.position) > deadZone)
         transform.position = Vector3.Lerp(transform.position, v3, speed * Time.deltaTime);
 }