var navArrowFollow = function(wrapper, navElemArray, activeID, arrowX, y0ffset, speed) {
	var yerHere = new Fx.Tween($(wrapper), { 
		duration: speed,
		transition: Fx.Transitions.Sine.easeInOut
	});
	$$(navElemArray).each(function(item){  
		item.addEvent('mouseenter', function() { 
			var thisPos = item.getPosition(wrapper).y  + item.getSize().y - y0ffset; 
			yerHere.cancel();
			yerHere.start('background-position', arrowX + 'px ' + thisPos + 'px'); 
		});
	});	
	var curArrow = function() {
		yerHere.cancel();
		var actPos = $(activeID).getPosition(wrapper).y  + $(activeID).getSize().y - y0ffset; 
		yerHere.start('background-position', arrowX + 'px ' + actPos + 'px');      
	};	 
	//correct IE rendering problem (without this, it wont go to the active nav onload)
	var actPos = $(activeID).getPosition(wrapper).y  + $(activeID).getSize().y - y0ffset;  
	$(wrapper).setStyle('background-position', arrowX + 'px ' + actPos + 'px');       	
	//works to set image to starting position in other browsers
	curArrow(); 	
	$(wrapper).addEvent('mouseleave', curArrow);	
};