Classes > onEnterFrame doesnt work?

Hey

disclaimer: have been working too hard, too long - so if this is as simple as abc , please excuse … but do help :frowning:
This is a simplified vesion of the problem :

I made a class named “fo” :

class fo {
	function onEnterFrame(){
	 trace("HERE");	
	}
}

the swf file calling this file had:

var tr:fo = new fo();

Now when i run this swf … it traces nothing … ???

( The as file is named fo.as and is in the same foledr as the swf file )