When use composite component Myfaces throws exception "Cannot cast UIpanel to panelGroup" - exception

Question

I made some research and i found a guy who have the same problem below(Its is in portugueshttps://groups.google.com/forum/#!topic/javasf/OBPyBP6Sfjs) but the site that he gave dont exist anymore and he don't answer my email for 2 days so...
Problem is: whenever i use an composite component i got that exception (even if they are empty just for test):
javax.servlet.ServletException: javax.faces.component.UIPanel cannot
be cast to javax.faces.component.html.HtmlPanelGroup
javax.faces.webapp.FacesServlet.service(FacesServlet.java:606)
org.springframework.orm.jpa.support.OpenEntityManagerInViewFilter.doFilterInternal(OpenEntityManagerInViewFilter.java:147)
org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
root cause
java.lang.ClassCastException: javax.faces.component.UIPanel cannot be
cast to javax.faces.component.html.HtmlPanelGroup
org.apache.myfaces.shared.renderkit.html.HtmlGroupRendererBase.encodeEnd(HtmlGroupRendererBase.java:65)
javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:875)
javax.faces.component.UIComponent.encodeAll(UIComponent.java:1786)
org.apache.myfaces.renderkit.html.HtmlCompositeComponentRenderer.encodeEnd(HtmlCompositeComponentRenderer.java:71)
javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:875)
javax.faces.component.UIComponent.encodeAll(UIComponent.java:1786)
javax.faces.component.UIComponent.encodeAll(UIComponent.java:1782)
javax.faces.component.UIComponent.encodeAll(UIComponent.java:1782)
com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:402)
org.apache.myfaces.application.ViewHandlerImpl.renderView(ViewHandlerImpl.java:285)
com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:121)
com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:139)
javax.faces.webapp.FacesServlet.service(FacesServlet.java:594)
org.springframework.orm.jpa.support.OpenEntityManagerInViewFilter.doFilterInternal(OpenEntityManagerInViewFilter.java:147)
org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
For me look likes that when you use an composite, myfaces try to generate an panel and for some reason the exception is throwed, and just to remember that i made this test with the body having only the composite and composite itself is empty(with interface and implementation sections).
I am using Myfaces 2.1.11, tomcat 7(pluging for maven), jsf 2.0, hibernate.