Destorying game object not working

Hello, I am a new Unity user with some programming skills. Getting straight to the point I am making a game that when I press the shift key down "fire2" it creates a smallish wall in front of me and stops movement except turning. That works. but when I release the shift key up I want it to destroy the wall I just created. I have 3 objects. Character, Wall and Enemy.

on the character I have created a script called EnergyBlockFire and that code is;

 //Variables - blockprefab is the wall - charPrefab is the character
 var charPrefab:Transform;
 var blockPrefab:Transform;
 
 function Update () 
 {
 if(Input.GetButtonDown("Fire2")) // button down
     {
     Movement.blocking = true; //stopping movement

     //spawns the wall
     var bullet = Instantiate(blockPrefab, 
                  gameObject.Find("WallSpawnPoint").transform.position,
                  Quaternion.identity); 

     }
     //this bit works.. when I release the shift key it 
     //enables me to move which is what I want
     if(Input.GetButtonUp("Fire2"))
     {
     Movement.blocking = false;
 }
 }
 

on the wall prefab I have created a script called EnergyBlockDestroy and the code is;

 //enemy bullet collides with wall - this works
 function OnTriggerEnter( hit : Collider)
 {
     if(hit.gameObject.tag == "enemyfireball") 
     {
     Movement.blocking = false;
     Destroy(gameObject);
     Destroy(hit.gameObject);
     }
 }

how ever this is the bit I am stuck at, it doesn't destroy the wall, no errors at all, i can after that place more walls down but it wont let me. the wall is called "BlockWall" both prefab and object in the game. it is also tagged as wallblock.

 function update ()
 {
     if (Input.GetButtonUp("Fire2"))
     {
     Destroy(gameObject);
     }
 }

I understand with this it may be confusing so I uploaded it to the internet incase anyone needs to download it to look for them self's. Please help I really don't know why its not working. thank you!

Game Download -

http://www.megaupload.com/?d=QZCKILYJ

thankyou!