Thanks for your help Dean. The version of MyFaces distributed with JBP 2.6.1 is 1.1.1 and the version of Seam I use is 1.1.6 GA. I tried to use MyFaces 1.1.4 which is distributed with JB 4.0.5. I replace the jars into jboss-portal-2.6.1.GA\server\default\deploy\jboss-portal.sar\portal-admin.sar\portal-admin.war\WEB-INF\lib2 and into my WAR, but I have the same result. Here is the stackTrace: java.lang.IllegalArgumentException: Class org.jboss.seam.jsf.SeamApplicationFactory is no javax.faces.application.ApplicationFactory at javax.faces.FactoryFinder.newFactoryInstance(FactoryFinder.java:132) at javax.faces.FactoryFinder.getFactory(FactoryFinder.java:107) at org.apache.myfaces.config.FacesConfigurator.configureApplication(FacesConfigurator.java:439) at org.apache.myfaces.config.FacesConfigurator.configure(FacesConfigurator.java:141) at org.apache.myfaces.portlet.MyFacesGenericPortlet.initMyFaces(MyFacesGenericPortlet.java:184) at org.apache.myfaces.portlet.MyFacesGenericPortlet.init(MyFacesGenericPortlet.java:110) at javax.portlet.GenericPortlet.init(GenericPortlet.java:270) at org.jboss.portal.portlet.impl.jsr168.PortletContainerImpl.initPortlet(PortletContainerImpl.java:359) at org.jboss.portal.portlet.impl.jsr168.PortletContainerImpl.start(PortletContainerImpl.java:233) at org.jboss.portal.portlet.impl.container.PortletApplicationContextImpl.startPortletApplication(PortletApplicationContextImpl.java:130) at org.jboss.portal.portlet.deployment.jboss.PortletAppDeployment.start(PortletAppDeployment.java:153) at org.jboss.portal.core.deployment.jboss.PortletAppDeployment.start(PortletAppDeployment.java:94) at org.jboss.portal.server.deployment.jboss.DeploymentContext.start(DeploymentContext.java:99) at org.jboss.portal.server.deployment.jboss.PortalDeploymentInfoContext.start(PortalDeploymentInfoContext.java:211) at org.jboss.portal.server.deployment.jboss.ServerDeployer.start(ServerDeployer.java:217) at org.jboss.deployment.MainDeployer.start(MainDeployer.java:1025) at org.jboss.deployment.MainDeployer.deploy(MainDeployer.java:819) at sun.reflect.GeneratedMethodAccessor212.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:585) at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:155) at org.jboss.mx.server.Invocation.dispatch(Invocation.java:94) at org.jboss.mx.interceptor.AbstractInterceptor.invoke(AbstractInterceptor.java:133) at org.jboss.mx.server.Invocation.invoke(Invocation.java:88) at org.jboss.mx.interceptor.ModelMBeanOperationInterceptor.invoke(ModelMBeanOperationInterceptor.java:142) at org.jboss.mx.server.Invocation.invoke(Invocation.java:88) at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264) at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659) ... What I don't understand is when I use JBP 2.6.0.CR2 with JB 4.0.5, MyFaces 1.1.4 and Seam 1.1.6 GA it works, but when I use the same versions of MyFaces and Seam on JBP 2.6.1 with JB 4.2.1, it tells me that SeamApplicationFactory is no ApplicationFactory ! I'll try to look what does MyFacesGenericPortlet while init. Thanks. JP View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4069948#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...