prova così:

codice:
<title>TITOLO PAGINA</title>
<link rel="stylesheet" href="styles.css" type="text/css" media="screen, projection" />
<script type="text/javascript" src="jquery-1.4.2.min.js"></script>
<script type="text/javascript" src="jquery.tools.min.js"></script>
<link href="./scrollable-horizontal.css" rel="stylesheet" type="text/css" media="all" />
<link href="./scrollable-buttons.css" rel="stylesheet" type="text/css" media="all" />
<link rel="stylesheet" href="css/lightbox.css" type="text/css" media="screen" />
<script src="js/prototype.js" type="text/javascript"></script>
<script src="js/scriptaculous.js?load=effects" type="text/javascript"></script>
<script src="js/lightbox.js" type="text/javascript"></script>

<script> var J = jQuery.noConflict(); </script>
<script>
// execute your scripts when the DOM is ready. this is a good habit 
J(function() { 

// initialize scrollable 
J("div.scrollable").scrollable(); 

}); 
</script>

</head>