UCE0001 even though i got the semicolon right (i think)

i was making a game through this tutorial (ill link it) and even though it worked for the guy on the tutorial it doesnt work for me the mono devolop asked me to accept something and i did but it was a wrong choice i guess so if somone knows anything about it please help me this is the link: https://www.youtube.com/watch?v=N49cfP-MWJA this is the code:

 #pragma strict
 
 var rotationSpeed = 100;
 this code is for making a ball move right and left
 
 function Update () 
 {
       var rotation : float Input.GetAxis ("Horizontal") * rotationSpeed;
       rotation *= Time.deltaTime;
       rigidbody.AddRelativeTorque (Vector3.back * (rotation);
 }