Unity compiler throwing fake errors? Something wrong with this script.

See for yourselves, tell me if you see something wrong here. This is driving me crazy for two days!

 var bulletPrefab : Rigidbody; 
 
 var initialForce : float = 200.0;
 var Spawnpoint : Transform;
 var Gunsmoke : Transform;
 var Firerate : float = 1.0;
 var NextShot : float = Firerate;
 var CanFire : boolean = true;
 
 function Update()  {
     if (Input.GetButtonDown ("Fire1")) {
         if (CanFire == true) {
             Fire ();
             CanFire = false;
             NextShot = 0;
         }
     }
     if (NextShot <== Firerate) {
         Firerate + NextShot * Time.deltaTime;
     }
     if (NextShot >== Firerate {
         CanFire = true;
     }
 }
 
 function Fire()  {
     if (Input.GetButtonDown ("Fire1")) {
         var bulletClone : Rigidbody;
         bulletClone = Instantiate( bulletPrefab, Spawnpoint.position, Spawnpoint.rotation );
         Instantiate(Gunsmoke, Spawnpoint.position, Spawnpoint.rotation);
 
         bulletClone.AddForce( bulletClone.transform.forward * initialForce, ForceMode.Force );
      }
 }