Help with .click .animate having to click twice in IE

Help with .click .animate having to click twice in IE

Hi all,
I have written some Jquery code to animate a div, basically a horizotal sliding drawer. The problem is, it has to be clicked twice in IE 7 to make it work, but only once in FF and safari like it should. Any help would be greatly appreicated.

Thanks.

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
   <head>
      <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
      <title>Untitled Document</title>
      <script src="lib/jquery/jquery-1.3.2.js" type="text/javascript"></script>
      
        <script type="text/javascript">      
      $(document).ready(function() {
           $("#rtbutton").click(function() {
          var $marginRt = $('.rtinner');
             $marginRt.animate({
                 marginRight:parseInt($marginRt.css('marginRight'),0)==0?$marginRt.outerWidth():0    
              });   
            });
            $("#rtbutton").click(function() {
                $(".horzarrows").toggleClass("bgposition"); return false;
             });
         });
         </script>

<style>
body {
   margin: 0;

.rtslide {
   width: 100%;
    overflow: hidden;
   position: absolute;
    float: right;
}
.rtinner {
    background: url(images/slide_img.png) no-repeat 0px 0px;   
    position: relative;
    width: 250px;
    height: 162px;
    right: -250px;
    float: right; 
}
#rtbutton {
   background: url(vert_slidebtn_img.png) no-repeat 0px 4px;
   width: 38px;
   height: 153px;
   margin-left: -30px;
   float: left;
}
.horzarrows {
   background: url(images/horz_arrows.png) no-repeat 12px 0px;
   width: 73px;
   height: 10px;
   float: left;
   margin: 18px 0 0 0;
}
.bgposition {
   background-position: -49px 0px;
}
     </style>   
   </head>
   <body>   
     <div class="rtslide">
       <div class="rtinner">
          <div id="rtbutton">
            <div class="horzarrows"></div>
          </div>
        </div>
      </div>
   </body>
</html>