problem ze skryptem "fixed block" java classie.js

[AZADA_M]

witam

na każdej stronie wywala mi błąd 

<script>
    function init() {
        window.addEventListener('scroll', function(e){
            var distanceY = window.pageYOffset || document.documentElement.scrollTop,
                shrinkOn = 160,
                header = document.querySelector(".footer_order");
            if (distanceY > shrinkOn) {
                classie.add(header,"fixed_block");
            } else {
                if (classie.has(header,"fixed_block")) {
                    classie.remove(header,"fixed_block");
                }
            }
        });
    }
    window.onload = init();
</script>	

o co chodzi ?? jak to usunąć.