Code:
<html>
<head><title>Exemplo</title>
<script type='text/javascript' src='core.js'></script>
<script type='text/javascript'>
var Accordion = 
{
   init: function()
   {
      var accordions = Core.getElementsByClass("accordion");
	  for(var i = 0; i < accordions.length; i++)
	  {
	     var folds = accordions[i].childNodes;
		 for( var j = 0; j < folds.length; j++)
		 {
		    if(folds[j].noteType == 1)
			{
			   Accordion.collapse(folds[j]);
			   var foldLinks = folds[j].getElmentsbyTagName("a");
			   var foldTitleLink = foldLinks[0];
			   Core.addEventListener(foldTitleLink, "click", Accordion.clickListener);
			   for(var k = 1; foldLinks.length; k++)
			   {
			      Core.addEventListener(foldLinks[k], "focus", Accordion.focusListener);
			   }
			}
		 }
		 if(location.hash.length > 1)
		 {
		    var activeFold = document.getElementById(location.hash.substring(1));
			if(activeFold && activeFold.parentNode == accordions[i])
			{
			   Accordion.expand(activeFold);
			}
		 }
	  }
   },
   
   collapse: function(fold)
   {
      Core.removeClass(fold, "expanded");
	  Core.addClass(fold, "collapsed");
   },
   
   collapseAll: function(accordion)
   {
      var folds = accordion.childNodes;
	  for(var i = 0; i < folds.length; i++)
	  {
	     if(folds[i].nodeType == 1)
		 {
		    Accordion.collapse(folds[i]);
		 }
	  }
   },
   
   expand: function(fold)
   {
      Accordion.collapseAll(fold.parentNode);
	  Core.removeClass(fold,"collapsed");
	  Core.addClass(fold, "expanded");  
   },
   
   clickListener: function(event)
   {
      var fold = this.parentNode.parentNode;
	  if(Core.hasClass(fold, "collapsed"))
	  {
	     Accordion.expand(fold);
	  }
	  else
	  {
	     Accordion.collapse(fold);
	  }
	  Core.preventDefault(event);
   },
   
   focusListener: function(event)
   {
      var element = this;
	  while(element.parentNode)
	  {
	     if(Core.hasClass(element.parentNode, "accordion"))
		 {
		    Accordion.expand(element);
			return;
		 }
		 element = element.parentNode;
	  }
   }
};

Core.start(Accordion);
</script>

<style type='text/css'>
ul.accordion li.collapsed * {  
  position: absolute;  
  left: -9999px;  
}  

ul.accordion li.collapsed h2, ul.accordion li.expanded h2,
ul.accordion li.collapsed h2 a:link,
ul.accordion li.collapsed h2 a:visited,
ul.accordion li.expanded h2 a:link,
ul.accordion li.expanded h2 a:visited{
position: static;
}

ul.accordion li.collapsed h2 a:hover,
ul.accordion li.collapsed h2 a:focus,
ul.accordion li.collapsed h2 a:active,
ul.accordion li.expanded h2 a:link,
ul.accordion li.expanded h2 a:visited {
background-color:#F0A000;
}
</style>
</head>
<body>
<ul class='accordion'>
  <li id="archer">
     <h2><a href="#archer">Jonathan Archer</a></h2>
	 <p>Vessel registry: NX-01</p>
	 <p>Assumed command: 2151</p>
	 <div class='links'>
	    <h3>Profiles</h3>
		<ul>
		   <li><a href="...">Memory Alpha</a></li>
		   <li><a href="...">Wikipedia</a></li>
		</ul>
	 </div>
  </li>
  <li id="pike">
     <h2><a href="#pike">Pike</a></h2>
	 <p>Vessel registry: NX-01</p>
	 <p>Assumed command: 2151</p>
	 <div class='links'>
	    <h3>Profiles</h3>
		<ul>
		   <li><a href="...">Memory Alpha</a></li>
		   <li><a href="...">Wikipedia</a></li>
		</ul>
	 </div>
  </li>
</ul>
</body>
</html>
Somebody knows which would be the error?
Exercise of the book alone Javascript, page 168.
Rodrigo - Brazil

Thank you