Regulary getting stack trace that feedback cannot be shown

Actual source or reproduction path unknown, but happens very frequently.

05.07.2010 10:13:40 ERROR [org.apache.wicket.RequestCycle.logRuntimeException():1521] Unable to find the markup for the component. That may be due to transparent containers or components implementing IComponentResolver: [MarkupContainer [Component id = feedback]]
org.apache.wicket.WicketRuntimeException: Unable to find the markup for the component. That may be due to transparent containers or components implementing IComponentResolver: [MarkupContainer [Component id = feedback]]
at org.apache.wicket.MarkupFragmentFinder.find(MarkupFragmentFinder.java:125)
at org.apache.wicket.Component.locateMarkupStream(Component.java:3812)
at org.apache.wicket.Component.renderComponent(Component.java:2550)
at org.apache.wicket.ajax.AjaxRequestTarget.respondComponent(AjaxRequestTarget.java:828)
at org.apache.wicket.ajax.AjaxRequestTarget.respondComponents(AjaxRequestTarget.java:681)
at org.apache.wicket.ajax.AjaxRequestTarget.respond(AjaxRequestTarget.java:591)
at org.apache.wicket.request.AbstractRequestCycleProcessor.respond(AbstractRequestCycleProcessor.java:105)
at org.apache.wicket.RequestCycle.processEventsAndRespond(RequestCycle.java:1258)
at org.apache.wicket.RequestCycle.step(RequestCycle.java:1329)
at org.apache.wicket.RequestCycle.steps(RequestCycle.java:1428)
at org.apache.wicket.RequestCycle.request(RequestCycle.java:545)
at org.apache.wicket.protocol.http.WicketFilter.doGet(WicketFilter.java:479)
at org.apache.wicket.protocol.http.WicketFilter.doFilter(WicketFilter.java:312)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at org.hippoecm.frontend.ResourceRewriteFilter.doFilter(ResourceRewriteFilter.java:127)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at org.hippoecm.frontend.plugins.login.ConcurrentLoginFilter.doFilter(ConcurrentLoginFilter.java:54)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
at org.mortbay.jetty.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:230)
at org.mortbay.jetty.handler.HandlerCollection.handle(HandlerCollection.java:114)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.Server.handle(Server.java:326)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:923)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:547)
at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:212)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:409)
at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)