Getting three kinds of errors even after following the tutorial!

I am new to unity and am making my first game using the tutorial given by unity about making that ball rolling game.After creating the script for the player movement i get three errors namely CS0619, CS1061 and an internal error.Checked the whole script five times,and i had written same as the tutorial but still got the errors.Please help me by giving the answer by editing the question.The C# script is as follows:

 using UnityEngine;
 using System.Collections;
 
 public class Player_Controller : MonoBehaviour 
 {
     void Fixedupdate()
     {
         float moveHorizontal = Input.GetAxis("Horizontal");
         float moveVertical = Input.GetAxis("Vertical");
 
         Vector3 movement = new Vector3(moveHorizontal, 0.0f, moveVertical);
     
         rigidbody.AddForce(movement);
     }
 }