Sou novo no JSF. Estou usando o Tomcat 7.0.14 e tentando executar o exemplo SimpleHelloByEnteringName, mas obtendo os seguintes erros na inicialização e no tempo de execução

ensagem do @Startup Console:

INFO: Deploying web application directory SimpleHelloByEnteringName
Jun 15, 2011 7:35:42 AM com.sun.faces.config.ConfigureListener contextInitialized
INFO: Initializing Mojarra 2.0.3 (FCS b03) for context '/SimpleHelloByEnteringName'
Jun 15, 2011 7:35:43 AM com.sun.faces.spi.InjectionProviderFactory createInstance
INFO: JSF1048: PostConstruct/PreDestroy annotations present.  ManagedBeans methods marked with these annotations will have said annotations processed.

**Jun 15, 2011 7:35:44 AM com.sun.faces.config.processor.NavigationConfigProcessor addNavigationCasesForRule
WARNING: JSF1058: The resource referred to by to-view-id, 'result.jsp', for navigation from '/pages/inputname.jsp', does not start with '/'.  This will be added for you, but it should be corrected.**

Jun 15, 2011 7:35:44 AM com.sun.faces.config.ConfigureListener$WebConfigResourceMonitor$Monitor <init>
INFO: Monitoring jndi:/localhost/SimpleHelloByEnteringName/WEB-INF/faces-config.xml for modifications
Jun 15, 2011 7:35:44 AM org.apache.coyote.AbstractProtocolHandler start
INFO: Starting ProtocolHandler ["http-apr-8081"]
Jun 15, 2011 7:35:44 AM org.apache.coyote.AbstractProtocolHandler start
INFO: Starting ProtocolHandler ["ajp-apr-8009"]
Jun 15, 2011 7:35:44 AM org.apache.catalina.startup.Catalina start

e erro de tempo de execução ao tentar executarhttp: // localhost: 8081 / SimpleHelloByEnteringName /

HTTP Status 500 -

type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

javax.servlet.ServletException: java.lang.NoClassDefFoundError: javax/el/ELResolver
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:342)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:722)

root cause

java.lang.NoClassDefFoundError: javax/el/ELResolver
    java.lang.ClassLoader.defineClass1(Native Method)
    java.lang.ClassLoader.defineClassCond(ClassLoader.java:631)
    java.lang.ClassLoader.defineClass(ClassLoader.java:615)
    java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141)
    java.net.URLClassLoader.defineClass(URLClassLoader.java:283)
    java.net.URLClassLoader.access$000(URLClassLoader.java:58)
    java.net.URLClassLoader$1.run(URLClassLoader.java:197)
    java.security.AccessController.doPrivileged(Native Method)
    java.net.URLClassLoader.findClass(URLClassLoader.java:190)
    sun.misc.Launcher$ExtClassLoader.findClass(Launcher.java:229)
    java.lang.ClassLoader.loadClass(ClassLoader.java:306)
    java.lang.ClassLoader.loadClass(ClassLoader.java:295)
    sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
    java.lang.ClassLoader.loadClass(ClassLoader.java:295)
    java.lang.ClassLoader.loadClass(ClassLoader.java:247)
    org.apache.jasper.runtime.JspFactoryImpl.getJspApplicationContext(JspFactoryImpl.java:220)
    org.apache.jsp.index_jsp._jspInit(index_jsp.java:23)
    org.apache.jasper.runtime.HttpJspBase.init(HttpJspBase.java:49)
    org.apache.jasper.servlet.JspServletWrapper.getServlet(JspServletWrapper.java:171)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:356)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:333)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:722)

root cause

java.lang.ClassNotFoundException: javax.el.ELResolver
    java.net.URLClassLoader$1.run(URLClassLoader.java:202)
    java.security.AccessController.doPrivileged(Native Method)
    java.net.URLClassLoader.findClass(URLClassLoader.java:190)
    sun.misc.Launcher$ExtClassLoader.findClass(Launcher.java:229)
    java.lang.ClassLoader.loadClass(ClassLoader.java:306)
    java.lang.ClassLoader.loadClass(ClassLoader.java:247)
    java.lang.ClassLoader.defineClass1(Native Method)
    java.lang.ClassLoader.defineClassCond(ClassLoader.java:631)
    java.lang.ClassLoader.defineClass(ClassLoader.java:615)
    java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141)
    java.net.URLClassLoader.defineClass(URLClassLoader.java:283)
    java.net.URLClassLoader.access$000(URLClassLoader.java:58)
    java.net.URLClassLoader$1.run(URLClassLoader.java:197)
    java.security.AccessController.doPrivileged(Native Method)
    java.net.URLClassLoader.findClass(URLClassLoader.java:190)
    sun.misc.Launcher$ExtClassLoader.findClass(Launcher.java:229)
    java.lang.ClassLoader.loadClass(ClassLoader.java:306)
    java.lang.ClassLoader.loadClass(ClassLoader.java:295)
    sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
    java.lang.ClassLoader.loadClass(ClassLoader.java:295)
    java.lang.ClassLoader.loadClass(ClassLoader.java:247)
    org.apache.jasper.runtime.JspFactoryImpl.getJspApplicationContext(JspFactoryImpl.java:220)
    org.apache.jsp.index_jsp._jspInit(index_jsp.java:23)
    org.apache.jasper.runtime.HttpJspBase.init(HttpJspBase.java:49)
    org.apache.jasper.servlet.JspServletWrapper.getServlet(JspServletWrapper.java:171)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:356)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:333)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:722)

note The full stack trace of the root cause is available in the Apache Tomcat/7.0.14 logs.

Como esse problema é causado e como posso resolvê-lo?