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)