GameObject go = (GameObject)Instantiate(GameObject.Find("Flames"), new Vector3(0.0f, 0.0f, 0.0f));
//For the new vector3, type the position where you want it to appear.
I think what is missing here, and can be seen in the scripting manual on instantiate, is that you create a variable in the script that is exposed in the inspector. Choose the prefab in the inspector using the popup menu, and you are set. Right?
var prefab : Transform;
function Start() {
myPrefab=Instantiate(prefab,Vector3.zero,Quaternion.identity);
}