Walker boys tutorial... NullPointerException error

Im seeing the Walker boys tutorial, Im on the Project #2, where you make a ship that destroys asteroids… and there’s a part where the bullet must call a function from other object… (here’s the video 5 16 scene manager score on Vimeo) I do everything that is here but I get this error:

"NullReferenceException: Object reference not set to an instance of an object
scriptBullet.OnTriggerEnter (UnityEngine.Collider other) (at Assets/scriptBullet.js:39)

and that line of code is :

sceneManager.transform.GetComponent(scriptsceneManager).AddScore();

scriptsceneManager.js

var gameTime : float = 60;
 static var score : int = 0;
function Update () 
{
print("score : " +score);

}

public function AddScore()
{
 score +=1;
}

Your class name starts with upper case, you refer to it in your GetComponent with lower case.

In general, cases of names of things much ALWAYS match exactly or they are different names.