Switching Cameras

Hi there, I've been trying to switch between my cameras mid-game, but the same error keeps coming up. Here are the scripts I've been using:

 var camera1 : Camera; 
 var camera2 : Camera; 
 //camera1 being the main camera, and camera2 being a still one that just overlooks
 var IsSwitched = false;
 var IsNotSwitched = true;
 
 function Start () { 
    camera1.enabled = true; 
    camera2.enabled = false; 
 } 
  
 function Update () { 
    if(IsSwitched){ 
       camera1.enabled = false; 
       camera2.enabled = true; 
    } 
    if (IsNotSwitched){ 
       camera1.enabled = true; 
       camera2.enabled = false; 
    }     
 }

And here is the other script, attached to an object that when touched, switches the cameras:

 var ScriptHolder : SwitchCamera1;
 
 function OnTriggerEnter(hit : Collider) {
 ScriptHolder.IsSwitched = true;
 ScriptHolder.IsNotSwitched = false;
 Destroy(gameObject);
 }

And it works just fine with switching the cameras; however, this error came up, concerning the object that is the player (the [ ] is where the script is located, but isn't word-for-word the exact location):

NullReferenceException ThirdPersonController.UpdateSmoothedMovementDirection () (at [script location]:105) ThirdPersonController.Update () (at [script location]:320)

Note: I have the OrbitCamera script attached to the main camera, obviously focused upon the player object, and the ThirdPersonController script on the player.

The only problem is this error; everything else works fine. I'd like to know what I'm doing wrong here. Thanks for helping!