JSF 1.2 to 2.0 migration exception with el-api.jar - jsf

Question

We are migrating our application which was developed using JSF1.2 to JSF2.0 on WAS7 .Also we have decided to use view technology as JSP. We have made the required changes(jars,web.xmland faces-config.xml) as suggested in:
Migrating from JSF 1.2 to JSF 2.0
We are also using richfaces components and we have upgraded library to richfaces3.3.3.
We are getting following exception while using h:commandlink and h:commandbutton:
Exception created : javax.servlet.ServletException
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:325)
at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:1657)
at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:1597)
at com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java:131)
at org.ajax4jsf.webapp.BaseXMLFilter.doXmlFilter(BaseXMLFilter.java:206)
at org.ajax4jsf.webapp.BaseFilter.handleRequest(BaseFilter.java:290)
at org.ajax4jsf.webapp.BaseFilter.processUploadsAndHandleRequest(BaseFilter.java:388)
at org.ajax4jsf.webapp.BaseFilter.doFilter(BaseFilter.java:515)
at com.ibm.ws.webcontainer.filter.FilterInstanceWrapper.doFilter(FilterInstanceWrapper.java:188)
at com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java:116)
at org.apache.myfaces.webapp.filter.ExtensionsFilter.doFilter(ExtensionsFilter.java:341)
at com.ibm.ws.webcontainer.filter.FilterInstanceWrapper.doFilter(FilterInstanceWrapper.java:188)
at com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java:116)
at com.xxx.yyy.webapp.security.LoginFilter.doFilter(LoginFilter.java:201)
at com.ibm.ws.webcontainer.filter.FilterInstanceWrapper.doFilter(FilterInstanceWrapper.java:188)
at com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java:116)
at com.ibm.ws.webcontainer.filter.WebAppFilterChain._doFilter(WebAppFilterChain.java:77)
at com.ibm.ws.webcontainer.filter.WebAppFilterManager.doFilter(WebAppFilterManager.java:908)
at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:934)
at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:502)
at com.ibm.ws.webcontainer.servlet.ServletWrapperImpl.handleRequest(ServletWrapperImpl.java:181)
at com.ibm.ws.webcontainer.servlet.CacheServletWrapper.handleRequest(CacheServletWrapper.java:91)
at com.ibm.ws.webcontainer.WebContainer.handleRequest(WebContainer.java:864)
at com.ibm.ws.webcontainer.WSWebContainer.handleRequest(WSWebContainer.java:1592)
at com.ibm.ws.webcontainer.channel.WCChannelLink.ready(WCChannelLink.java:186)
at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleDiscrimination(HttpInboundLink.java:452)
at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleNewRequest(HttpInboundLink.java:511)
at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.processRequest(HttpInboundLink.java:305)
at com.ibm.ws.http.channel.inbound.impl.HttpICLReadCallback.complete(HttpICLReadCallback.java:83)
at com.ibm.ws.tcp.channel.impl.AioReadCompletionListener.futureCompleted(AioReadCompletionListener.java:165)
at com.ibm.io.async.AbstractAsyncFuture.invokeCallback(AbstractAsyncFuture.java:217)
at com.ibm.io.async.AsyncChannelFuture.fireCompletionActions(AsyncChannelFuture.java:161)
at com.ibm.io.async.AsyncFuture.completed(AsyncFuture.java:138)
at com.ibm.io.async.ResultHandler.complete(ResultHandler.java:204)
at com.ibm.io.async.ResultHandler.runEventProcessingLoop(ResultHandler.java:775)
at com.ibm.io.async.ResultHandler$2.run(ResultHandler.java:905)
at com.ibm.ws.util.ThreadPool$Worker.run(ThreadPool.java:1646)
Caused by: java.lang.UnsupportedOperationException
at javax.faces.context.FacesContext.getELContext(FacesContext.java:223)
at javax.faces.application.NavigationCase.getToViewId(NavigationCase.java:264)
at com.sun.faces.application.NavigationHandlerImpl.determineViewFromActionOutcome(NavigationHandlerImpl.java:580)
at com.sun.faces.application.NavigationHandlerImpl.findExactMatch(NavigationHandlerImpl.java:345)
at com.sun.faces.application.NavigationHandlerImpl.getViewId(NavigationHandlerImpl.java:279)
at com.sun.faces.application.NavigationHandlerImpl.handleNavigation(NavigationHandlerImpl.java:159)
at org.apache.myfaces.custom.redirectTracker.RedirectTrackerNavigationHandler.handleNavigation(RedirectTrackerNavigationHandler.java:40)
at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:130)
at javax.faces.component.UICommand.broadcast(UICommand.java:315)
at org.ajax4jsf.component.AjaxActionComponent.broadcast(AjaxActionComponent.java:55)
at org.ajax4jsf.component.AjaxViewRoot.processEvents(AjaxViewRoot.java:329)
at org.ajax4jsf.component.AjaxViewRoot.broadcastEventsForPhase(AjaxViewRoot.java:304)
at org.ajax4jsf.component.AjaxViewRoot.processPhase(AjaxViewRoot.java:261)
at org.ajax4jsf.component.AjaxViewRoot.processApplication(AjaxViewRoot.java:474)
at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:82)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:118)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:312)
Root causes seems to be related to expression language.We do not have el-api.jar in our WEB-INF/lib as recommended and we have set classloader policy to PARENT_LAST at both server and application level. WAS7 has j2ee5 jar in its lib directory.