万网云主机建站首页幻灯片图片不能正常显示

<script type="text/javascript" src="$_G['style'][styleimgdir]/images/jquery.touchSlider.js"></script>
<script type="text/javascript" src="$_G['style'][styleimgdir]/images/jquery.event.drag-1.5.min.js"></script>
<script type="text/javascript">
jQuery(document).ready(function () {
    jQuery(".main_visual").hover(function(){
        jQuery("#btn_prev,#btn_next").fadeIn()
        },function(){
        jQuery("#btn_prev,#btn_next").fadeOut()
        })
    jQuerydragBln = false;
    jQuery(".main_image").touchSlider({
        flexible : true,
        speed : 200,
        btn_prev : jQuery("#btn_prev"),
        btn_next : jQuery("#btn_next"),
        paging : jQuery(".flicking_con a"),
        counter : function (e) {
            jQuery(".flicking_con a").removeClass("on").eq(e.current-1).addClass("on");
        }
    });
    jQuery(".main_image").bind("mousedown", function() {
        jQuerydragBln = false;
    })
    jQuery(".main_image").bind("dragstart", function() {
        jQuerydragBln = true;
    })
    jQuery(".main_image a").click(function() {
        if(jQuerydragBln) {
            return false;
        }
    })
    timer = setInterval(function() { jQuery("#btn_next").click();}, 5000);
    jQuery(".main_visual").hover(function() {
        clearInterval(timer);
    }, function() {
        timer = setInterval(function() { jQuery("#btn_next").click();}, 5000);
    })
    jQuery(".main_image").bind("touchstart", function() {
        clearInterval(timer);
    }).bind("touchend", function() {
        timer = setInterval(function() { jQuery("#btn_next").click();}, 5000);
    })
});
</script>


        <div class="main_visual">
          <div class="flicking_con">
            <div class="flicking_inner"> <a href="javascript:">1</a> <a href="javascript:">2</a> <a href="javascript:">3</a> <a href="javascript:">4</a> <a href="javascript:">5</a> </div>
          </div>
          <div class="main_image">
            <ul>
              <li><a href="#" target="_blank" title=""><span style="background:url($_G['style'][styleimgdir]/images/img_main_1.jpg) center top no-repeat"></span></a></li>
              <li><a href="#" target="_blank" title=""><span style="background:url($_G['style'][styleimgdir]/images/img_main_2.jpg) center top no-repeat"></span></a></li>
              <li><a href="#" target="_blank" title=""><span style="background:url($_G['style'][styleimgdir]/images/img_main_3.jpg) center top no-repeat"></span></a></li>
              <li><a href="#" target="_blank" title=""><span style="background:url($_G['style'][styleimgdir]/images/img_main_4.jpg) center top no-repeat"></span></a></li>
              <li><a href="#" target="_blank" title=""><span style="background:url($_G['style'][styleimgdir]/images/img_main_5.jpg) center top no-repeat"></span></a></li>


            </ul>
            <a href="javascript:;" id="btn_prev"></a> <a href="javascript:;" id="btn_next"></a> </div>
        </div>
是什么原因？