java.lang.ClassNotFoundException: com.sun.faces.config.FacesInitializer

I am using Liferay v6.2 CE & I am getting the following error:

 2015 2:14:34 ΜΜ org.apache.catalina.startup.ContextConfig getServletContainerInitializer
SEVERE: The ServletContentInitializer [com.sun.faces.config.FacesInitializer] could not be created
java.lang.ClassNotFoundException: com.sun.faces.config.FacesInitializer
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1714)
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1559)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:270)
    at org.apache.catalina.startup.ContextConfig.getServletContainerInitializer(ContextConfig.java:1652)
    at org.apache.catalina.startup.ContextConfig.processServletContainerInitializers(ContextConfig.java:1562)
    at org.apache.catalina.startup.ContextConfig.webConfig(ContextConfig.java:1270)
    at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:878)
    at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:376)
    at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119)
    at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5322)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:901)
    at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:877)
    at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:633)
    at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1113)
    at org.apache.catalina.startup.HostConfig$DeployDirectory.run(HostConfig.java:1671)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
    at java.util.concurrent.FutureTask.run(FutureTask.java:262)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:744)

Φεβ 12, 2015 2:14:34 ΜΜ org.apache.catalina.startup.ContextConfig processServletContainerInitializers

Any help what is going wrong?