细节问题怎么解决：图片移动多次后总是错位。

细节问题怎么解决：图片移动多次后总是错位。
我需要很多排图片向上分组移动，但前几排很好，多移动一会就开始慢慢错位了，请大虾相助。
代码如下：

<style type=text/css>
a:link { text-decoration:none; color:#0000FF;}
a:vISIted { text-decoration:none; color:#000000;}
a:hover { text-decoration:underline; color:#b67e16;}
a:active { text-decoration:none; color:#FF9900;}
table,body { font-family: "宋体"; font-size: 9pt;}
TD {FONT-SIZE: 9pt ; COLOR: #000000; LINE-HEIGHT: 100%}
</style>
<div align="center">
<DIV id=icefable1 style="overflow:hidden;height:80px;line-height:0px">
<table border="0" cellspacing="0" cellpadding="0" width="775" align="center" height="80">
<tr valign="MIDDLE" align="center">
<td width="100%" height="80" bgcolor="#CC99FF">第1排</td>
</tr>
<tr valign="MIDDLE" align="center">
<td width="100%" bgcolor="#666666" height="80">第2排</td>
</tr>
<tr valign="MIDDLE" align="center">
<td width="100%" bgcolor="#33CC33" height="80">第3排</td>
</tr>
<tr valign="MIDDLE" align="center">
<td width="100%" bgcolor="#006699" height="80">第4排</td>
</tr>
<tr valign="MIDDLE" align="center">
<td width="100%" bgcolor="#FF9999" height="80">第5排</td>
</tr>
<tr valign="MIDDLE" align="center">
<td width="100%" bgcolor="#33FFCC" height="80">第6排</td>
</tr>
<tr valign="MIDDLE" align="center">
<td width="100%" bgcolor="#99FF99" height="80">第7排</td>
</tr>
<tr valign="MIDDLE" align="center">
<td width="100%" bgcolor="#FF0000" height="80">第8排</td>
</tr>
</table></DIV><DIV id=icefable2 style="Z-INDEX: 5; VISIBILITY: hidden; POSITION: absolute;height:80px;line-height:0px"></DIV></div>
<SCRIPT>
marqueesHeight=80;stopscroll=false;
icefable1.scrollTop=0;with(icefable1){
style.width=0;style.height=marqueesHeight;style.overflowX='visible';style.overflowY='hidden';
noWrap=true;onmouseover=new Function('stopscroll=true');onmouseout=new Function('stopscroll=false');}preTop=0; currentTop=0;stoptime=0;
function init_srolltext()
{icefable2.innerHTML='';icefable2.innerHTML+=icefable1.innerHTML;
icefable1.innerHTML=icefable2.innerHTML+icefable2.innerHTML;
setInterval('scrollUp()',6);}
function scrollUp()
{if(stopscroll==true) return;currentTop+=1;
if(currentTop==80){stoptime+=1;currentTop-=1;
if(stoptime==80){currentTop=0;stoptime=0;}}else{preTop=icefable1.scrollTop;icefable1.scrollTop+=1;
if(preTop==icefable1.scrollTop){ icefable1.scrollTop=icefable2.offsetHeight-marqueesHeight;
icefable1.scrollTop+=1;
}}}
init_srolltext();
</SCRIPT>
<SCRIPT FOR='EccoolAd' EVENT='fscommand()' LANGUAGE='JavaScript'>
AdLayer1.style.visibility='hidden';
AdLayer2.style.visibility='hidden';
</script>