Here's the code (just change enable to "true" and it produces a .pdf, but with enable="false" I get the exception):
<root xmlns:pd4ml="http://pd4ml.com/tlds/pd4ml/2.6"
xmlns:jsp="http://java.sun.com/JSP/Page"
xmlns:c="http://java.sun.com/jsp/jstl/core"><pd4ml:transform enable="false"
pageFormat="A4"
pageOrientation="Portrait"
screenWidth="610"
pageInsets="10,50,20,50,points"
enableTableBreaks="true"
inline="false"
fileName="hello.pdf"
debug="true"><pd4ml:usettf from="java:fonts" serif="Times New Roman" sansserif="Arial" monospace="Courier New"/><pd4ml:permissions password="empty" rights="2068" strongEncryption="false"/><html xmlns:html="http://www.w3.org/1999/xhtml"
xmlns:tiles="http://tiles.apache.org/tags-tiles"
xmlns:form="http://www.springframework.org/tags/form"
xmlns:spring="http://www.springframework.org/tags"
xmlns:roo="urn:jsptagdir:/WEB-INF/tags"
xmlns:security="http://www.springframework.org/security/tags" version="2.0">
<jsp:output doctype-root-element="HTML" doctype-public="-//W3C//DTD XHTML 1.0 Strict//EN"
doctype-system="http://www.w3.org/TR/xhtml1/DTD/xhtml-strict.dtd"/>
<jsp:directive.page contentType="text/html;charset=UTF-8" />
<jsp:directive.page pageEncoding="UTF-8" />
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<meta http-equiv="X-UA-Compatible" content="IE=8" />
<link rel="stylesheet" href="/contabilita/css/int/general.css" type="text/css"/>
<link rel="stylesheet" href="/contabilita/css/int/header.css" type="text/css"/>
<script type="text/javascript" src="/javascript/mootools141.js"><!-- required by FF and opera --></script>
<title>A title</title>
</head>
<body>
<div id="wrapperVit">
<tiles:insertAttribute name="header" ignore="true" />
<div id="main" style="padding-top: 10px;">
<tiles:insertAttribute name="body"/>
</div>
</div>
</body>
</html>
</pd4ml:transform>
</root>
