Cannot create document type through the interface

As reported by Jeroen Reijn; Still can't create document type through the interface without different kind of errors

When adding the second field of type 'Text':

28.04.2009 14:14:38 WARN [org.hippoecm.frontend.JcrObservationManager$JcrListener.process():408] Root node no longer exists: hippo:namespaces/defaultcontent/eigentype/hippo:nodetype/hippo:nodetype/hippo:field[2]

After that the CMS hangs and I get the following Wicket error:

28.04.2009 14:18:56 ERROR [org.apache.wicket.RequestCycle.logRuntimeException():1437] After 1 minute the Pagemap null is still locked by: Thread[btpool0-7,5,main], giving up trying to get the page for path: 5:root:pinger
org.apache.wicket.WicketRuntimeException: After 1 minute the Pagemap null is still locked by: Thread[btpool0-7,5,main], giving up trying to get the page for path: 5:root:pinger
at org.apache.wicket.Session.getPage(Session.java:740)
at org.apache.wicket.request.AbstractRequestCycleProcessor.resolveRenderedPage(AbstractRequestCycleProcessor.java:448)
at org.apache.wicket.protocol.http.WebRequestCycleProcessor.resolve(WebRequestCycleProcessor.java:139)
at org.apache.wicket.RequestCycle.step(RequestCycle.java:1233)
at org.apache.wicket.RequestCycle.steps(RequestCycle.java:1353)
at org.apache.wicket.RequestCycle.request(RequestCycle.java:493)
at org.apache.wicket.protocol.http.WicketFilter.doGet(WicketFilter.java:355)
at org.apache.wicket.protocol.http.WicketFilter.doFilter(WicketFilter.java:200)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1084)
at org.hippoecm.frontend.plugins.login.ConcurrentLoginFilter.doFilter(ConcurrentLoginFilter.java:54)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1084)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:360)
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:181)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:726)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:405)
at org.mortbay.jetty.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:206)
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:324)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:505)
at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:829)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:514)
at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:211)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:380)
at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:395)
at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:488)