Help for CSS Menu Dropdown, FF OK and IE6 Problem

Question

IE Problem, FF OK. Please help..????

The problem is when hover in menu Transaction to show dropdown.

Screen Shoot problem click here

This is my CSS :

<style type="text/css">

#dolphincontainer   {  
position:relative;
height:56px;
color:#E0E0E0;
background:#143D55;
width:100%;
font-family:Tahoma;
left: 0px;}  

#dolphinnav{position:absolute;;height:33px;font-size:12px;font-weight:bold;background:#fff url(images/dolphin_bg.gif) repeat-x bottom left;padding:0 0 0 10px;width:975px;}  
#dolphinnav ul {margin:0;padding:0;list-style-type:none;width:auto;float:left;}
#dolphinnav ul li{display:block;float:left;margin:0 1px;}
#dolphinnav ul li a{display:block;float:left;color:#001b2c;text-decoration:none;padding:0 0 0 10px;height:33px;}
#dolphinnav ul li a span{padding:12px 20px 0 0;height:21px;float:left;font-weight:bold;}
#dolphinnav ul li a:hover{color:#fff;background:transparent url(images/dolphin_bg-OVER.gif) repeat-x bottom left;}
#dolphinnav ul li a:hover span{display:block;width:auto;cursor:pointer;}
#dolphinnav ul li a.current,#dolphinnav ul li a.current:hover{color:#fff;background:#00517e url(images/dolphin_left-ON.gif) no-repeat top left;line-height:275%;}
#dolphinnav ul li a.current span {display:block;padding:0 20px 0 0;width:auto;background:#00517e url(images/dolphin_right-ON.gif) no-repeat top right;height:33px;}


 .tuckUp{
display:block;
width:90px;
height:30px;
overflow:hidden;
cursor:pointer;}
  .pullDown{
width:90px;
height:56px;}
  .item a:link, .item a:visited{
display:inline;
float:left;
background:#fff url(images/dolphin_bg.gif) repeat-x top left;padding:0 0 0 10px;
text-align:left;
color:#444;
font-size:11px;
font-weight:bold;
text-decoration:none;
line-height:25px;
margin:0 5px 0px 0px;
width:80px;}
   .item a:hover{
display:inline;
float:left;
background:#39c;
color:#FFF;
text-decoration:none;
text-align:left;
font-size:11px;
font-weight:700;
font-weight:bold;
line-height:25px;
padding:0 0 0 10px;
margin:0 5px 0px 0px;
width:80px;}
</style>

HTML:

<div id="dolphincontainer">     
          <div id="dolphinnav">     
            <ul>      
              <li><a href="index.php"><span>Home</span></a></li>  
              <li><a href="chooseus.php"><span>Why Choose Us</span></a></li>  
              <li><a href="peraturan.php"><span>Rules</span></a></li>  
              <li class="tuckUp" onmousemove="this.className='pullDown'" onmouseout="this.className='tuckUp'"><a href="#"><span>Transaction</span></a>   
                <div class="item"> <a href="drop1.php">Drop Down 1</a><br />  
                  <a href="drop2.php">Drop Down 2</a></a><br />  
                  <a href="drop3.php">Drop Down 3</a><br />  
                </div>  
              </li>  
              <li><a href="download.php"><span>Download</span></a></li>  
              <li><a href="aboutus.php"><span>About Us</span></a></li>  
              <li><a href="help.php" class="current"><span>Support</span></a></li>  
              <li><a href="promo.php"><span><font color="#FF0000"><blink>PROMO</blink>  </font></span></a></li>  
            </ul>  
          </div>  
        </div>