The referenced script on this Behaviour is missing! please help me

public class PlayerMovement: MonoBehaviour { public float speed = 6f;

  Vector3 movement;
  Animator anim;
  Rigidbody playerRigidbody;
  int floorMask;
  float camRayLength = 100f;
  
  void Awake()
  {
      floorMask = LayerMask.GetMask ("Floor");
      anim = GetComponent <Animator> ();
      playerRigidbody = GetComponent<Rigidbody> ();
  }
  
  void FixedUpdate()
  {
      float h = Input.GetAxisRaw ("Horizontal");
      float v = Input.GetAxisRaw ("Vertical");
      
      Move (h, v);
      Turning ();
      Animating (h, v);
  }
  
  void Move (float h, float v)
  {
      movement.Set (h, 0f, v);
      
      movement = movement.normalized * speed * Time.deltaTime;
      
      playerRigidbody.MovePosition (transform.position + movement);
  }
  
  void Turning()
  {
      Ray camRay = Camera.main.ScreenPointToRay (Input.mousePosition);
      
      RaycastHit floorHit;
      
      if (Physics.Raycast (camRay, out floorHit, camRayLength, floorMask))
      {
          Vector3 playerToMouse = floorHit.point - transform.position;
          playerToMouse.y = 0f;
          
          Quaternion newRotation = Quaternion.LookRotation (playerToMouse);
          playerRigidbody.MoveRotation (newRotation);    
      }    
  }
  
  void Animating(float h, float v)    
  {
      bool walking = h != 0f || v != 0f;
      
      anim.SetBool ("IsWalking", walking);
  }    

}