Problema com aplicação WEB + antlr/ANTLRException

Colegas,
Estou desenvolvendo uma aplicação WEB com:
- JSF
- Hibernate
- Spring
- Sitemesh

Buenas, 
      Quando rodo no servidor de homologação:
                  Linux Ubuntu 7.04 - Java 1.6 - Tomcat 5.5.20
                 Tudo funciona que é um beleza.

       Quando rodo no servidor de produção:
                  Slackware 10 - Java 1.5 - Tomcat 5.5.9
                 Em todas as páginas de listagem da essa maldita exception:
javax.servlet.jsp.JspException: javax.faces.el.EvaluationException: Error getting property 'listaDeSecretarias' from bean of type br.com.simcaweb.web.ReportSecretaria: java.lang.NoClassDefFoundError: antlr/ANTLRException
	at com.sun.faces.taglib.html_basic.PanelGridTag.doEndTag(PanelGridTag.java:470)
	at org.apache.jsp.reportSecretaria_jsp._jspx_meth_h_panelGrid_0(reportSecretaria_jsp.java:367)
	at org.apache.jsp.reportSecretaria_jsp._jspx_meth_h_form_0(reportSecretaria_jsp.java:286)
	at org.apache.jsp.reportSecretaria_jsp._jspx_meth_f_view_0(reportSecretaria_jsp.java:169)
	at org.apache.jsp.reportSecretaria_jsp._jspService(reportSecretaria_jsp.java:99)
	at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
	at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:332)
	at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
	at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:72)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
	at com.opensymphony.module.sitemesh.filter.PageFilter.doFilter(PageFilter.java:39)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
	at br.com.simcaweb.web.MessageFilter.doFilter(MessageFilter.java:36)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
	at br.com.simcaweb.web.FiltroSeguranca.doFilter(FiltroSeguranca.java:40)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
	at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:672)
	at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:463)
	at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:398)
	at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:301)
	at com.sun.faces.context.ExternalContextImpl.dispatch(ExternalContextImpl.java:322)
	at com.sun.faces.application.ViewHandlerImpl.renderView(ViewHandlerImpl.java:130)
	at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:87)
	at com.sun.faces.lifecycle.LifecycleImpl.phase(LifecycleImpl.java:200)
	at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:117)
	at javax.faces.webapp.FacesServlet.service(FacesServlet.java:198)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
	at org.springframework.orm.hibernate3.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:174)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:77)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
	at com.opensymphony.module.sitemesh.filter.PageFilter.parsePage(PageFilter.java:118)
	at com.opensymphony.module.sitemesh.filter.PageFilter.doFilter(PageFilter.java:52)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
	at br.com.simcaweb.web.MessageFilter.doFilter(MessageFilter.java:36)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
	at br.com.simcaweb.web.FiltroSeguranca.doFilter(FiltroSeguranca.java:40)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:178)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
	at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:526)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
	at org.apache.jk.server.JkCoyoteHandler.invoke(JkCoyoteHandler.java:307)
	at org.apache.jk.common.HandlerRequest.invoke(HandlerRequest.java:385)
	at org.apache.jk.common.ChannelSocket.invoke(ChannelSocket.java:748)
	at org.apache.jk.common.ChannelSocket.processConnection(ChannelSocket.java:678)
	at org.apache.jk.common.SocketConnection.runIt(ChannelSocket.java:871)
	at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)
	at java.lang.Thread.run(Thread.java:595)
Alguma luz ?
Ob.: 
    -> Os class estão compilados para Source Level 1.5.
    -> O jar do antlr esta dentro do WEB-INF/lib.

Desde já agradecendo,
Um abraço,
Leandro