Compiling Error

Hello, I am a coder who is new to this program. I made a script but when I try to plug it in and start the play mode, in the inspector column, it said "The associated script can not be loaded. Please fix any compile errors and assign a valid script my script:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
namespace Moving {
namespace UnityEngine.Networking{
public class Behaviour : MonoBehaviour {
public float speed;
public Rigidbody rb;
void Start ()
{
rb = GetComponent<Rigidbody>();
}

// Update is called once per frame
void FixedUpdate () {
float moveUp = Input.GetAxis ("Horizontal");
float moveRight = Input.GetAxis ("Vertial");
Vector3 Move = new Vector3 (moveUp, 0.0f, moveRight);

rb.AddForce (Move * speed);

}
}
}
}