OnTriggerEnter

Hey all,

This is such a noob question, I have used this code before I even copied it from another project I was working on.

 var target : Transform;    
 
 function Start () {    
 }
 
 function Update () {    
 }
 
 function OnTriggerEnter (trig : Collider){
     if(trig.gameObject.tag == "enemy"){
             Debug.Log("Detected!");
     }
 }

It's not rocket science is it? But this is attached to a sphere with a trigger, and I have another object Tagged enemy. But it simply will not Debug.

This is probably a school boy error but I can't make it work. please help!

Steve