I would love to know how to keep spawning enemies because when i shoot them they don't spawn. The cause is that the prefab is missing as it says heres my code

[Unity3DJava]

var zombiePrefab : GameObject;
var zombiesSpawned : int;
var player : GameObject;
var spawn : boolean;
var minWait : int;
var maxWait : int;
var waitTime : int;

function Start()
{
minWait = 1;
maxWait = 1;
waitTime = Random.Range(minWait, maxWait);;
spawn = true;
}


function Update()
{
if(spawn)
{

Spawn();

}

}


function Spawn()
{

//spawn
Instantiate(zombiePrefab, transform.position, transform.rotation);//spawn at spawner location
zombiesSpawned += 1;
NewWaitTime();
spawn = false;

SetSpawn();
}

function SetSpawn()
{
	yield WaitForSeconds(waitTime);
	spawn = true;
}


function NewWaitTime()
{
waitTime = Random.Range(minWait, maxWait);
}

[robertbu]

Typically this happens if a person doesn’t use a real prefab. Instead the person uses a game object from the scene and in game play it is killed. One fix is to use a real prefab.

In the Project Pane, right mouse click and select Create/Prefab. Drag the object you want to be a prefab on top of the gray prefab icon. Then drag this prefab on top of zombiePrefab variable.

At this point you can delete the original object (or not).