NullPointerException while starting up MWS

When I issued “mws.bat start”, I got below error.
Any idea why?

[POP.001.0002] A “java.lang.NullPointerException” occurred with the Message “at com.webmethods.portal.portlet.wm_xt_portalrules.mechanics.PortalRulesMechanics.createFacesContext(PortalRulesMechanics.java:842)”
java.lang.NullPointerException
at com.webmethods.portal.portlet.wm_xt_portalrules.mechanics.PortalRulesMechanics.createFacesContext(PortalRulesMechanics.java:842)
at com.webmethods.portal.portlet.wm_xt_portalrules.mechanics.PortalRulesMechanics.initPortalRulesFacesContext(PortalRulesMechanics.java:810)
at com.webmethods.portal.portlet.wm_xt_portalrules.mechanics.PortalRulesMechanics.preparePortalRuleContext(PortalRulesMechanics.java:779)
at com.webmethods.portal.portlet.wm_xt_portalrules.mechanics.PortalRulesMechanics.getRuleResultForUser(PortalRulesMechanics.java:390)
at com.webmethods.portal.framework.impl.PortalServlet.getStartPageRuleForUser(PortalServlet.java:706)
at com.webmethods.portal.framework.impl.PortalServlet.getUserStartPage(PortalServlet.java:688)
at com.webmethods.portal.framework.impl.PortalServlet.acquireURI(PortalServlet.java:658)
at com.webmethods.portal.system.PortalSystem.acquireURI(PortalSystem.java:701)
at com.webmethods.portal.portlet.wm_xt_usertabset.mechanics.UsertabsetMechanics$RootPageResolver.acquireURI(UsertabsetMechanics.java:59)
at com.webmethods.portal.system.PortalSystem.acquireURI(PortalSystem.java:701)
at com.webmethods.portal.portlet.wm_xt_portalrules.rules.PortalRuleContext.(PortalRuleContext.java:33)
at com.webmethods.portal.portlet.wm_xt_portalrules.mechanics.PortalRulesMechanics.getRuleContext(PortalRulesMechanics.java:212)
at com.webmethods.portal.portlet.wm_xt_portalrules.mechanics.PortalRulesMechanics.getRuleContext(PortalRulesMechanics.java:205)
at com.webmethods.portal.portlet.wm_xt_portalrules.mechanics.PortalRulesMechanics.getRuleForUser(PortalRulesMechanics.java:438)
at com.webmethods.portal.portlet.impl.wm_xt_skin.mechanics.SkinMechanics.getCurrentSkinID(SkinMechanics.java:524)
at com.webmethods.portal.framework.presentation.PresentationManager.setSessionData(PresentationManager.java:539)
at com.webmethods.portal.framework.presentation.PresentationManager.preparePresentationData(PresentationManager.java:240)
at com.webmethods.portal.framework.dispatch.DispatchManager.preparePresentationData(DispatchManager.java:812)
at com.webmethods.portal.framework.dispatch.DispatchManager.handle(DispatchManager.java:434)
at com.webmethods.portal.framework.dispatch.DispatchManager.handleDispatch(DispatchManager.java:370)
at com.webmethods.portal.framework.impl.PortalServlet.service(PortalServlet.java:266)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166)
at com.webmethods.portal.framework.impl.NTLMFilter.doFilter(NTLMFilter.java:50)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.webmethods.caf.faces.servlet.GZIPFilter.doFilter(GZIPFilter.java:42)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
at org.mortbay.jetty.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:230)
at org.mortbay.jetty.handler.HandlerCollection.handle(HandlerCollection.java:114)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.Server.handle(Server.java:326)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:923)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:547)
at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:212)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:409)
at org.mortbay.thread.BoundedThreadPool$PoolThread.run(BoundedThreadPool.java:451)

Problem was gone after applying latest service packs.