ConcurrentModificationException upon starting the wiki

2009-09-14 12:38:32,187 [http://localhost:8080/xwiki/bin/edit/Sandbox/L?&editor=wysiwyg] [http://localhost:8080/xwiki/bin/edit/Sandbox/L?&editor=wysiwyg] ERROR xwiki.XWiki                     - Failed to send document save notifications for document [XWiki.WatchListJobClass] 
java.util.ConcurrentModificationException
	at java.util.HashMap$HashIterator.nextEntry(HashMap.java:841)
	at java.util.HashMap$ValueIterator.next(HashMap.java:871)
	at org.xwiki.observation.internal.DefaultObservationManager.notify(DefaultObservationManager.java:253)
	at org.xwiki.observation.internal.DefaultObservationManager.notify(DefaultObservationManager.java:232)
	at com.xpn.xwiki.XWiki.saveDocument(XWiki.java:1330)
	at com.xpn.xwiki.plugin.watchlist.WatchListJobManager.initWatchListJobClass(WatchListJobManager.java:151)
	at com.xpn.xwiki.plugin.watchlist.WatchListJobManager.init(WatchListJobManager.java:280)
	at com.xpn.xwiki.plugin.watchlist.WatchListPlugin.init(WatchListPlugin.java:116)
	at com.xpn.xwiki.plugin.XWikiPluginManager.initPlugin(XWikiPluginManager.java:155)
	at com.xpn.xwiki.plugin.XWikiPluginManager.addPlugin(XWikiPluginManager.java:92)
	at com.xpn.xwiki.plugin.XWikiPluginManager.addPlugins(XWikiPluginManager.java:120)
	at com.xpn.xwiki.XWiki.preparePlugins(XWiki.java:1046)
	at com.xpn.xwiki.XWiki.initXWiki(XWiki.java:751)
	at com.xpn.xwiki.XWiki.<init>(XWiki.java:682)
	at com.xpn.xwiki.XWiki.getMainXWiki(XWiki.java:319)
	at com.xpn.xwiki.XWiki.getXWiki(XWiki.java:400)
	at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:135)
	at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:115)
	at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431)
	at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
	at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
	at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:414)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
	at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:502)
	at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
	at com.xpn.xwiki.wysiwyg.server.filter.ConversionFilter.doFilter(ConversionFilter.java:155)
	at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1148)
	at com.xpn.xwiki.web.ActionFilter.doFilter(ActionFilter.java:117)
	at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1148)
	at com.xpn.xwiki.plugin.webdav.XWikiDavFilter.doFilter(XWikiDavFilter.java:68)
	at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1148)
	at com.xpn.xwiki.web.SavedRequestRestorerFilter.doFilter(SavedRequestRestorerFilter.java:295)
	at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1148)
	at com.xpn.xwiki.web.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:112)
	at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1148)
	at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:387)
	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:765)
	at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:417)
	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:534)
	at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:864)
	at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:539)
	at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:212)
	at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
	at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:409)
	at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:520)