Problem med dynamisk meny

Har kört fast fullständigt med en meny som ska öppna undermenyer vid klick på ett alternativ.

Jag får hela tiden "document.getElementById("menu" + intX) has no properties"

Skulle vara mycket tacksam om nån kunde hjälpa mig.

<script language="JavaScript" type="text/javascript">
/*<![CDATA[*/
function Shift_Menu(menuId){
    for(intX=1;intX<=5;intX++){
		document.getElementById("menu"+intX).className="notactive";
		document.getElementById("sub_menu"+intX).className="notactive";
    }
    document.getElementById(menuId).className="active";
    document.getElementById("sub_"+menuId).className="active";
}
/*]]>*/
</script>

<style type="text/css">
<!--
#topmenu li {
	float: left;
  	cursor: pointer;
	list-style-type: none;
	height: 12px
}

#topmenu .active{
	background-color:#5A7C99;
	color:#ffffff;
	margin : 0px 0px 0px 0px;
	padding: 4px 0px 4px 0px;
}

#topmenu .notactive{
	background-color:#FDFDFD;
	text-align:center;
	color:#000000;
	margin : 0px 0px 0px 0px;
	padding: 4px 0px 4px 0px;
}

#topmenu {
	font : 12px "Trebuchet MS", Arial, sans-serif;
	text-align : center;
	line-height : 11px;
	font-weight : bold;
	margin : 0px 0px 0px 0px;
	padding : 0;
	letter-spacing: 1px;
	background-color:#FDFDFD;
}
#submenu {
	font : 11px "Trebuchet MS", Arial, sans-serif;
	float:left;
	width : 570px;
	margin : 0px 0px 1px 0px;
	padding : 0px;
	clear : both;
	color: #243078;
	background-color : #1C5582 ;
}

#submenu a {
	font : 11px Arial, sans-serif;
	color : #FFFFFF;
	text-decoration : none;
	margin : 0px 5px 0 5px;
	font-weight: 700
}

#submenu a:hover {
	color : #FFFFFF;
}

#submenu li {
	font : 11px Arial, sans-serif;
	list-style-type : none;
	height : 16px;
	padding:1px;
	margin : 0px 0px 0px 0px;
}

#submenu .active{
	display : block;
  	background-color : #5A7C99;
}

#submenu .notactive{
 	display : none;
}
-->
</style>

<div style="position:relative; float:left; margin-bottom:5px; margin-left:3px; width:570px; background-color: #FFFFFF ; height:40px; border-bottom: 2px solid #E1E1E1;">
  <ul id="topmenu">
    <li class="notactive" id="menu1" style="width:142px;" onclick="Shift_Menu(this.id);">Start</li>
    <li class="notactive" id="menu2" style="width:143px;" onclick="Shift_Menu(this.id);">Forum</li>
    <li class="notactive" id="menu3" style="width:142px;" onclick="Shift_Menu(this.id);">Medlemmar</li>
    <li class="active" id="menu4" style="width:143px;" onclick="Shift_Menu(this.id);">&Ouml;vrigt</li>
  </ul>
  <ul id="submenu">
    <li class="notactive" id="sub_menu1">
      <a href="default.asp?page=admStart">Start</a> | 
      <a href="default.asp?page=admNews">Nyheter</a> | 
      <a href="default.asp?page=admPoll">Webbfr&aring;gan</a>
    </li>
    <li class="notactive" id="sub_menu2">
      <a href="default.asp?page=admForum">Forum kategorier</a> | 
      <a href="default.asp?page=admMod">Moderatorer</a> | 
    </li>
    <li class="notactive" id="sub_menu3">
      <a href="default.asp?page=admPhoto">Bilder</a> | 
      <a href="default.asp?page=admWarnings">Varningar</a> | 
      <a href="default.asp?page=admBlocked">Avst&auml;gningar</a> | 
      <a href="default.asp?page=admBanned">Blockeringar</a>
    </li>
    <li class="active" id="sub_menu4">
      <a href="default.asp?page=admArticles">Artiklar</a> | 
      <a href="default.asp?page=admLinks">L&auml;nkar</a> | 
      <a href="default.asp?page=admBooks">Bokrecensioner</a>
    </li>
  </ul>	
</div>

<div style="width:564px; padding:3px; text-align:left;">
  <a href="default.asp?page=admNoob&amp;action=newNoob">L&auml;gg till nyb&ouml;rjarkurs</a>
</div><div style="width:564px; padding:3px; text-align:left;"><hr/></div>
<div class="white_sub" style="width:564px; padding:3px; text-align:left; font-weight:bold;">
  <a href="default.asp?page=admBooks&amp;action=editBooks&amp;bookId=1">Bok 3</a>
</div>
<div class="white_sub" style="width:564px; padding:3px; text-align:left; font-weight:bold;">
  <a href="default.asp?page=admBooks&amp;action=editBooks&amp;bookId=2">Bok 2</a>
</div>
<div class="white_sub" style="width:564px; padding:3px; text-align:left; font-weight:bold;">
  <a href="default.asp?page=admBooks&amp;action=editBooks&amp;bookId=3">Bok 3</a>
</div>

for(intX=1;intX<=5;intX++)
   ->
for(intX=1;[b]intX<5[/b];intX++)