Problema com Export excel displaytag

<%@page import="br.com.getnet.valegas.controller.mbean.PinMBean"%>
 <%@page import="java.util.*"%>
 <%@ taglib uri="http://displaytag.sf.net" prefix="display"%>
 
 <%
 	List pinsVendidos = PinMBean.getListaPinsVendidos();
 	request.setAttribute("pinsVendidos", pinsVendidos);
 %>
 
 <table align="center" class="tabelaPrincipal" width="740">
 	<tr>
 		<td>
 		<h3>Relatório de Pins Vendidos</h3>
 		</td>
 	</tr>
 	<tr>
 		<td><display:table name="pinsVendidos" export="true"
 			id="tabelaPinsVendidos"
 			requestURI="/relatorios/relatorioPINs.jsf">
 			<display:column property="pin" title="Pin" class="campoListagem"
 				sortable="true" />
 			<display:column property="estabelecimento" title="Estabelecimento"
 				class="campoListagem" sortable="true" />
 			<display:column property="dataCriacao" title="Data de Criacao"
 				class="campoListagem" sortable="true" />
 			<display:column property="valor" title="Valor" class="campoListagem"
 				sortable="true" />
 			<display:column property="descricaoProduto"
 				title="Descricao do Produto" class="campoListagem" sortable="true" />
 			<display:column property="situacao" title="Situacao"
 				class="campoListagem" sortable="true" />
 			<display:column property="dataAutorizacao" title="Data Autorizacao"
 				class="campoListagem" sortable="true" />
 
 
 			<div class="campoListagem"><display:setProperty
 				name="paging.banner.placement" value="bottom" /> 
 				
 				<display:setProperty
 				name="export.excel.class"
 				value="org.displaytag.export.excel.ExcelHssfView" /> 
 				
 				<display:setProperty
 				name="export.excel" value="true" /> 
 				
 				<display:setProperty
 				name="export.excel.class"
 				value="org.displaytag.export.DefaultPdfExportView" /> 
 				
 				<display:setProperty
 				name="export.pdf" value="true" /> 
 				
 				<display:setProperty
 				name="export.pdf.filename" value="teste.pdf" />
 
 				<display:setProperty name="export.excel.filename" 
 				value="teste.xls" /></div>
 
 		</display:table></td>
 	</tr>
 </table>

servlet.ServletException: ServletException in ‘/relatorioPINs.jsp’: null

javax.faces.webapp.FacesServlet.service(FacesServlet.java:121)

br.com.getnet.valegas.controller.filter.AuthorizationFilter.doFilter(AuthorizationFilter.java:65)

br.com.getnet.valegas.controller.filter.AuthenticationFilter.doFilter(AuthenticationFilter.java:55)

org.springframework.orm.hibernate3.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:174)

org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:77)

org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:60)

org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:77)

org.apache.myfaces.component.html.util.ExtensionsFilter.doFilter(ExtensionsFilter.java:122)