Object reference not set to instance of an object

The tough part about programming is that sometimes, our 100% certainty doesn't amount to 100% of the truth. ;)

If I were you, I'd build up that line of code with gradual Debug.Logs to see if the calls to GameObject.Find and GetComponent actually do return what you're 100% positive they do.

You shouldn't use Find if that's inside Update, my tip is to first off variable "First Person Controller" (var fpc : Transform). Also later variable the whole fpc.GetComponent(CharacterController) in Start () as so:

 cController = fpc.GetComponent(CharacterController);

If it's an if ("boolean") you can also instead negate with:

 if (!fpc.cController.grounded)

The first steps will give you a real performance boost.

 var fpc : Transform;
 var cController;
 function Start () {
     cController = fpc.GetComponent(CharacterController);
 }
 function Update () {
     if (!fpc.cController.grounded) {
         //Character is jumping/falling
     }
 }

Hopefully t$$anonymous$$s might also solve your issue. Most of the times when t$$anonymous$$s happens it's because the variable you're trying to reach inside an object or the name of the object is called or spelled differently (I'm not familiar with the CharacterController class). I t$$anonymous$$nk that grounded is reached from the actual CharacterController instead of CharacterMotor though.