Rotation around a moving object.

This question has been asked & I have searched for solutions but after applying one that seems like it should work I get odd results.

I have a rolling sphere in game & what I want is so that the up arrow rolls the ball forward, relative to the camera's direction but without effecting the Y axis, also my camera wants to be able to rotate around the ball with the left & right arrows. All of this seems to work at first but after playing around in my world for a little while I noticed my camera started banking at odd angles for no reason I can figure out. So, here is my code! Hierarchy: Sphere>Right way up>Main Camera

Attached to the camera

 var targetCube : Transform;
 var speed = 10;
 
 function Update() {
 
 
     // spin the object around the target at 10 degrees/second.
 
 
 
     if (Input.GetKey (KeyCode.LeftArrow)) {
     transform.RotateAround (targetCube.transform.position, Vector3.up, speed * Time.deltaTime);
     }
     if (Input.GetKey (KeyCode.RightArrow)) {
     transform.RotateAround (targetCube.transform.position, Vector3.up, speed * -Time.deltaTime);
     }
 
 }

Then attached to 'Right way up' is this:

     function Update () {
 transform.eulerAngles = Vector3(0,0,0);
         
 }

Lastly there is my movement (which right now does not zero out the force on the Y axis)

 function Update(){
 
 if(Input.GetKey(KeyCode.UpArrow)){
 rigidbody.AddTorque(Camera.main.transform.right * 1);
 }
 }

Any insight that anyone can provide would be accepted gladly, thanks.