Fehler:
java.lang.IncompatibleClassChangeError: Found class org.jivesoftware.openfire.muc.MUCRoom, but interface was expected

	at org.jivesoftware.openfire.plugin.candy.candy_002dconfig_jsp._jspService(candy_002dconfig_jsp.java:397)

	at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:71)

	at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)

	at org.jivesoftware.openfire.container.PluginServlet.handleJSP(PluginServlet.java:462)

	at org.jivesoftware.openfire.container.PluginServlet.service(PluginServlet.java:122)

	at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)

	at org.eclipse.jetty.servlet.ServletHolder$NotAsync.service(ServletHolder.java:1459)

	at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:799)

	at org.eclipse.jetty.servlet.ServletHandler$ChainEnd.doFilter(ServletHandler.java:1626)

	at org.jivesoftware.admin.PluginFilter.doFilter(PluginFilter.java:226)

	at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:193)

	at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1601)

	at org.jivesoftware.admin.AuthCheckFilter.doFilter(AuthCheckFilter.java:234)

	at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:193)

	at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1601)

	at com.opensymphony.sitemesh.webapp.SiteMeshFilter.obtainContent(SiteMeshFilter.java:129)

	at com.opensymphony.sitemesh.webapp.SiteMeshFilter.doFilter(SiteMeshFilter.java:77)

	at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:193)

	at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1601)

	at org.jivesoftware.util.LocaleFilter.doFilter(LocaleFilter.java:73)

	at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:193)

	at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1601)

	at org.jivesoftware.util.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:49)

	at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:193)

	at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1601)

	at org.jivesoftware.admin.PluginFilter.doFilter(PluginFilter.java:226)

	at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:193)

	at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1601)

	at org.jivesoftware.admin.AuthCheckFilter.doFilter(AuthCheckFilter.java:234)

	at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:201)

	at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1601)

	at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:548)

	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143)

	at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:602)

	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127)

	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:235)

	at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1624)

	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:233)

	at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1434)

	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:188)

	at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:501)

	at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1594)

	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:186)

	at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1349)

	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)

	at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:191)

	at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:146)

	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127)

	at org.eclipse.jetty.server.Server.handle(Server.java:516)

	at org.eclipse.jetty.server.HttpChannel.lambda$handle$1(HttpChannel.java:388)

	at org.eclipse.jetty.server.HttpChannel.dispatch(HttpChannel.java:633)

	at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:380)

	at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:277)

	at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:311)

	at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:105)

	at org.eclipse.jetty.io.ChannelEndPoint$1.run(ChannelEndPoint.java:104)

	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:338)

	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:315)

	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:173)

	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:131)

	at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:386)

	at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:883)

	at org.eclipse.jetty.util.thread.QueuedThreadPool$Runner.run(QueuedThreadPool.java:1034)

	at java.lang.Thread.run(Thread.java:748)