A Part of a Script Stops working when another object is not active.

A part of a gun script that rotates the gun around the player, stops working when a object that I'm not referencing in any way from the gun script.

In the gun script, everything works fine, until I disable that object. Then the gun stops rotating around the player, but it's able to shoot.

And, in the other object's script, or in any other, I don't disable any part of the gun script if the object is not active.

The object is something like a Building Cursor, and I want the player to be able to shoot just when the cursor is not active. But when that didn't work, I just replaced it for a backup, and it's still not working.

This is the part of the code that stops working. No if's.

     Vector3 orbVector = Camera.main.WorldToScreenPoint(orb.position);
                 orbVector = Input.mousePosition - orbVector;
                 float angle = Mathf.Atan2(orbVector.y, orbVector.x) * Mathf.Rad2Deg;
                 pivot.position = orb.position;
                 pivot.rotation = Quaternion.AngleAxis(angle - 90, Vector3.forward);

Thank you in advance.