IE7中用javascript写的图片的幻灯片浏览失效

这个是代码，测试在ie6中能自动播放。但是在ie7中则不行，运行后显示一个‘X’,要点击播放才能运行。。请问这个是怎么回事啊？   <script type="text/javascript">
    var imgUrl=new Array();
    var imgLink=new Array();
    var adNum=0;
    var stop=false;
    <% 
         int n=1;
         foreach (DataRow dr in ds1.Tables[0].Rows)
         { 
             Response.Write("imgUrl["+n+"]='"+ dr["PicPath"].ToString()+"';");
             n++;
         } 
    %>
    var imgPre=new Array();
    var j=0;
    for (i=1;i<<% =n %>;i++) {
     if( (imgUrl[i]!="") && (imgLink[i]!="") )
     {
         j++;
     } 
     else 
     {
         break;
     }
    }    function playTran()
    {
     if (document.all)
     document.getElementById("imgInit").filters.revealTrans.play();
    }
    function stopTran()
    {
        if(!stop)
        {
             if (document.all)
             document.getElementById("imgInit").filters.revealTrans.stop();
             stop=true;
             document.getElementById("btnPause").src="Images/play.jpg";
             document.getElementById("btnPause").alt="播放";
        }
        else
        {
            stop=false;
            document.getElementById("btnPause").src="Images/pause.jpg";
            document.getElementById("btnPause").alt="暂停";
            nextAd();
        }
    }
    var key=0;
    function nextAd()
    {
        if(!stop)
         {
             if(adNum<j)adNum++ ;
             else adNum=1;
             
             if( key==0 )
             {
                 key=1;
             } else if (document.all)
             {
                 document.getElementById("imgInit").filters.revealTrans.Transition=100;
                 document.getElementById("imgInit").filters.revealTrans.apply();
                 playTran();             }
             document.getElementById("imgInit").src=imgUrl[adNum];
             
            window.setTimeout(nextAd,6000);
         }
    }    function goUrl()
    {
         jumpUrl=imgLink[adNum];
         jumpTarget='_blank';
         if (jumpUrl != '')
         {
             if (jumpTarget != '') 
             window.open(jumpUrl,jumpTarget);
             else
             location.href=jumpUrl;
         }
    }
</script>