GameObject problem

In my scene I've an object with the HingeJoint, but If I Build the game, t$$anonymous$$s object dosn't appears..and the game is very slow! and if I remove the HingeJoint from t$$anonymous$$s object the G.Objects appears, and the game is fast.. why? In Play (in unity editor) it's all right!..

Maybe the settings of the HingeJoint are strange? I took a pic: http://img153.imageshack.us/img153/7681/ybbs.jpg

T$$anonymous$$s is the script:

 #pragma strict
 
 var amount = 5.0;
     
     
     
 function Awake ()
 {
  rigidbody.velocity = rigidbody.velocity * 0.0;
 }
 
 
     
 function Update()
 {
    if (Input.GetKey(KeyCode.R)) {
       rigidbody.AddForce(transform.right * amount);
    }
    else if (Input.GetKey(KeyCode.T)) {
       rigidbody.AddForce(-transform.right * amount);
    }
    else if (Input.GetKey(KeyCode.Y)) {
       rigidbody.velocity = rigidbody.velocity * 0.9;
    }
 }

Sorry for my bad english, I hope someone can help me!