Movement Script Only Works in One Scene

This is the movement script I have attached to my player character prefab. In my test scene it works perfectly fine, but if I create another instance of the prefab in any other scene, the camera rotation still works, but I cannot move the character or jump at all. How can that be?

 public class Move : MonoBehaviour 
 {
     public float speed;
     public float rotationSpeed;
     public float jumpHght;
     public float grav;
     bool jumping;
     bool moving;
     public AudioClip jumpSound;
     public AudioClip landSound;
     private Rigidbody rb;
 
     //Sets variables.
     void Start()
     {
         Physics.gravity = new Vector3(0, grav, 0);
         rb = GetComponent<Rigidbody>();
     }
 
     void Update() 
     {
         //Jumps, if MagBot is not already in air.
         if(Input.GetButtonDown("Jump") && jumping == false)
         {
             rb.AddForce(new Vector3(0, jumpHght, 0), ForceMode.Impulse);
             GetComponent<AudioSource>().PlayOneShot(jumpSound);
         }
     }
 
     //Determines when MagBot is not in air.
     void OnCollisionStay(Collision collision)
     {
         jumping = false;
     }
 
     //Determines when MagBot is in air.
     void OnCollisionExit(Collision collision)
     {
         if(!jumping)
         {
             jumping = true;
         }
     }
 
     //Plays collision sound effects after landing from jump.
     void OnCollisionEnter(Collision collision)
     {
         if(collision.gameObject.tag == "Envir") 
         {
             GetComponent<AudioSource>().PlayOneShot(landSound);
         }
     }
 
     void FixedUpdate() 
     {
         //Movement variables
         float v = Input.GetAxisRaw("Vertical") * speed;
         float h = Input.GetAxisRaw("Horizontal") * speed;
         float r = Input.GetAxisRaw("Mouse X") * rotationSpeed;
         v *= Time.deltaTime;
         h *= Time.deltaTime;
         r *= Time.deltaTime;
 
         //Rotates MagBot/camera based on mouse movement.
         transform.Rotate(0, r, 0);
 
         //Moves MagBot based on WASD/Left analog stick.
         rb.AddRelativeForce(0,0,-v, ForceMode.Impulse);
         rb.AddRelativeForce(h,0,0, ForceMode.Impulse);
     }
 }