CodingForums.com - jQuery Why am I such a noob?

I have no idea why this line of code isn't working--
http://vanishingpoint.b1.jcink.com/i...p?showtopic=14 (not advertising here lol)

I want to give .tableborder the id topictext for that page but it doesn't seem to be working
I can't edit the html template because it's a sad free forum host l0l

anywho this is the line of code that doesn't work
if it works the entire .tableborder shouldnt show because I had it set to display:none in my css

Code:

$("div.tableborder").hasClass("postlinksbar").attr("id","topictext");

the entire script

Code:

<script type="text/javascript">

if($("#userlinks td:contains('Welcome Guest')").length>0){

$("#userlinks td:contains('Welcome Guest')").wrapInner("<div id='lag1'></div>").html($("#userlinks td:contains('Welcome Guest')").html().replace(/Guest/, '<span class="guestbx">Guest</span>'));

}

$("div#lag1").insertBefore("#logostrip");

$("#navstrip").html($("#navstrip").html().replace(/&nbsp;/, '')).html($("#navstrip").html().replace(/Log In/, "<div id='navtext'>Login</div>"));

$("#menux a:last").attr("id","sadfix");

$("div#navstrip a:first-child").attr("id","original");

$("#menux a:last").hover(

function()

{$("div#stupidpad").css("background-image","url('http://vanishingpoint.b1.jcink.com/uploads/vanishingpoint//23125i.png')");}

,function()

{$("div#stupidpad").css("background-image","url('http://vanishingpoint.b1.jcink.com/uploads/vanishingpoint//23125g.png')");}

);

$("table").removeAttr("cellpadding").removeAttr("cellspacing").removeattr("border");

$("td.row2[nowrap]").addClass("postinfo");

$("div.tableborder").hasClass("postlinksbar").attr("id","topictext");

</script>