i try to run the tree demo with seam+richfaces, get errors.

[gringalet]

i try to run the tree demo with seam+richfaces, get errors. like this:

javax.servlet.ServletException: The absolute uri: http://richfaces.ajax4jsf.org/drag-drop cannot be resolved in either web.xml or the jar files deployed with this application
 javax.faces.webapp.FacesServlet.service(FacesServlet.java:154)
 org.ajax4jsf.framework.ajax.xmlfilter.BaseXMLFilter.doXmlFilter(BaseXMLFilter.java:127)
 org.ajax4jsf.framework.ajax.xmlfilter.BaseFilter.doFilter(BaseFilter.java:277)
 org.jboss.seam.web.ExceptionFilter.doFilter(ExceptionFilter.java:57)
 org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)


root cause

javax.faces.FacesException: The absolute uri: http://richfaces.ajax4jsf.org/drag-drop cannot be resolved in either web.xml or the jar files deployed with this application
 org.apache.myfaces.context.servlet.ServletExternalContextImpl.dispatch(ServletExternalContextImpl.java:425)
 org.apache.myfaces.application.jsp.JspViewHandlerImpl.renderView(JspViewHandlerImpl.java:211)
 org.jboss.seam.jsf.SeamViewHandler.renderView(SeamViewHandler.java:59)
 org.ajax4jsf.framework.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:108)
 org.ajax4jsf.framework.ajax.AjaxViewHandler.renderView(AjaxViewHandler.java:233)
 org.ajax4jsf.framework.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:108)
 org.ajax4jsf.framework.ajax.AjaxViewHandler.renderView(AjaxViewHandler.java:233)
 org.ajax4jsf.framework.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:108)
 org.ajax4jsf.framework.ajax.AjaxViewHandler.renderView(AjaxViewHandler.java:233)
 org.apache.myfaces.lifecycle.RenderResponseExecutor.execute(RenderResponseExecutor.java:41)
 org.apache.myfaces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:132)
 javax.faces.webapp.FacesServlet.service(FacesServlet.java:140)
 org.ajax4jsf.framework.ajax.xmlfilter.BaseXMLFilter.doXmlFilter(BaseXMLFilter.java:127)
 org.ajax4jsf.framework.ajax.xmlfilter.BaseFilter.doFilter(BaseFilter.java:277)
 org.jboss.seam.web.ExceptionFilter.doFilter(ExceptionFilter.java:57)
 org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)

there is no answer voice in richfaces forum. i feel i am ignored . so i come here ,who can tell me why,