关于FLV播放器加载，刚开始测试的时候是对的，后面不知道怎么不对了，求帮助


<p id="player1"><a href="http://www.macromedia.com/go/getflashplayer">Get the Flash Player</a> to see this player.</p>
                            <script type="text/javascript">
                                var s1 = new SWFObject("flvplayer.swf","single","640","480","7");
                                s1.addParam("allowfullscreen","true");
                                s1.addVariable("file","<%=videourl %>");
                                s1.addVariable("image","preview.jpg");
                                s1.addVariable("width","640");
                                s1.addVariable("height","480");
                                s1.write("player1");
                            </script>protected void Page_Load(object sender, EventArgs e)
        {
            if (!Page.IsPostBack)
            {
                this.btn6.Visible = false;
                BindSJ();
            }
        }        public string videourl = "";
        public string mpurl = "";        public void BindSJ()
        {
            int id = Convert.ToInt32(Request.QueryString["id"].ToString());
            VideoVO videoVO = new VideoVO(id);
            CourseVO courseVO = new CourseVO(videoVO.VideoCourseID);
            this.expertImage.ImageUrl = "/userfiles/images/" + courseVO.CourseExpertImage;
            this.expertNameLabel.Text = courseVO.CourseExpertName;
            this.expertUnitNameLabel.Text = courseVO.CourseExpertUnitName;
            this.expertIntroduction.Text = courseVO.CourseIntroduction;
            this.structureLabel.Text = videoVO.VideoStructure;
            videourl = videoVO.VideoUrl;
            if (videoVO.VideoType == "FLV")
            {
                videourl = videoVO.VideoUrl;
                this.flv.Visible = true;
                this.mp.Visible = false;
            }
            else
            {
                mpurl = videoVO.VideoUrl;
                this.mp.Visible = true;
                this.flv.Visible = false;
            }
        }
贴出了前后台代码，求解决。