After disabling then enabling this script it stops working anyone know why?

i used unity playmaker to disable and enable the script

using UnityEngine; using System.Collections;

public class Green : MonoBehaviour { public Transform Target; public float firingAngle = 45.0f; public float gravity = 9.8f;

 public Transform Projectile;
 private Transform myTransform;

 void Awake()
 {
     myTransform = transform;
 }

 void Start()
 {
     StartCoroutine(SimulateProjectile());
 }


 IEnumerator SimulateProjectile()
 {
     // Short delay added before Projectile is thrown
     yield return new WaitForSeconds(0.1f);

     // Move projectile to the position of throwing object + add some offset if needed.
     Projectile.position = myTransform.position + new Vector3(0, 0.0f, 0);

     // Calculate distance to target
     float target_Distance = Vector3.Distance(Projectile.position, Target.position);

     // Calculate the velocity needed to throw the object to the target at specified angle.
     float projectile_Velocity = target_Distance / (Mathf.Sin(2 * firingAngle * Mathf.Deg2Rad) / gravity);

     // Extract the X  Y componenent of the velocity
     float Vx = Mathf.Sqrt(projectile_Velocity) * Mathf.Cos(firingAngle * Mathf.Deg2Rad);
     float Vy = Mathf.Sqrt(projectile_Velocity) * Mathf.Sin(firingAngle * Mathf.Deg2Rad);

     // Calculate flight time.
     float flightDuration = target_Distance / Vx;

     // Rotate projectile to face the target.
     Projectile.rotation = Quaternion.LookRotation(Target.position - Projectile.position);

     float elapse_time = 0;

     while (elapse_time < flightDuration)
     {
         Projectile.Translate(0, (Vy - (gravity * elapse_time)) * Time.deltaTime, Vx * Time.deltaTime);

         elapse_time += Time.deltaTime;

         yield return null;
     }
 }

}