Trying to load a prefab via C# script

Okay - so here's the situation: I have a spider model as an FBX that loads fine - I also made a prefab inside unity (added colliders and other stuff to it) and exported it and have the prefab file.

Let's call the prefab new_spider and let's call the FBX just spider.

Enter Code:

Code (csharp):

1.             _main = GameObject.Find("Startup").GetComponent<Main>();
2.             GameObject spider = (GameObject)Resources.Load("npc/fantasySpider/spider_new");
3.             //Debug.Log("Calling spider");            
4.             spider.name = "Spider!";            
5.             Instantiate(spider, new Vector3(8216, 600, 8216), Quaternion.identity);    

Again the FBX loads fine with the above code but my prefab will not - I keep getting cast error

InvalidCastException: Cannot cast from source type to destination type.
GameEngine.Character.NPC.Start ()

I have googled and googled and cannot seem to load the prefab - any help is greatly appreciated! I have read about Transform and couldn't get that to work either.

Edit: I know that it is erroring out on this line: GameObject spider = (GameObject)Resources.Load("npc/fantasySpider/spider_new");

 

it doesn't seems to like the way you are casting, sometimes you have to cast it different so instead of saying:
(GameObject)Resources.Load("npc/fantasySpider/spider_new");

you should try instead: Resources.Load("npc/fantasySpider/spider_new") as GameObject;