error: namespace already contains definition

I keep getting a report saying Assets/Scripts/Ships/MissileLancher.js(9,6): BCE0132: The namespace '' already contains a definition for 'guntype'.

it has only one definition help?

 var reloadtime : float;
 var shot : GameObject;
 var numshots : int;
 var au : Object;
 private var Target : GameObject;
 
 enum guntype{
 singlefire,
 rapidfire,
 }
 
 
 function ChangeTarget(t : GameObject){
 Target = t;
 }
 
 
 
 var gunType : guntype;
 
 private var loaded : boolean = true;
 private var fireing : boolean = false;
 private var t : Transform;
 
 function Start(){
 t = transform;
 au = audio;
 }
 
 
 
 function FireCheck(){
 switch(gunType){
 case guntype.singlefire:
     if (loaded){Fire();}
     break;
 case guntype.rapidfire:
     if (loaded){Fire();}
     break;
 }
 }
 
 function Fire(){
 var s : GameObject;
 switch(gunType){
 case guntype.singlefire:
     s=Instantiate(shot,t.position,t.rotation);
     s.SendMessage("ChangeTarget",Target,SendMessageOptions.DontRequireReceiver);
     au.Play();
     loaded = false;
     yield WaitForSeconds(reloadtime);
     loaded = true;
     break;
 case guntype.rapidfire:
     for (i=1;i < numshots; i++){
     s=Instantiate(shot,t.position,t.rotation);
     au.Play();
     yield WaitForSeconds(0.15);
     }
     loaded = false;
     yield WaitForSeconds(reloadtime);
     loaded = true;
     break;
 }
 }

thanks