For some reason, jQuery's fade effect isn't working. Could it be because of the code?

This function does everything it is supposed to, aside from the fading. It gets called at the correct time.

function moveToTerm(original_course, helper, term) {

    var cloned_course = original_course.clone(true);

    original_course.addClass('already-scheduled');

    helper.fadeOut(function() {
        cloned_course.appendTo(term).attr('style', '').fadeIn("slow");
    });
}

UPDATE: It fails in both FF 3.5.9 and IE 8.