I am getting Many Exceptions in Openfire 3.7.0

Here is the link i got exception. http://localhost:9090/system-clustering.jsp …Can anyone explain why this is happening. i am very new to either XMPP or Openfire.

Exception:

java.lang.NoClassDefFoundError: com/tangosol/net/Invocable     at java.lang.Class.forName0(Native Method)     at java.lang.Class.forName(Class.java:247)     at org.jivesoftware.util.cache.CacheFactory.getMaxClusterNodes(CacheFactory.java:480)     at org.jivesoftware.util.cache.CacheFactory.isClusteringAvailable(CacheFactory.java:400)     at org.jivesoftware.openfire.cluster.ClusterManager.isClusteringAvailable(ClusterManager.java:344)     at org.jivesoftware.openfire.admin.system_002dclustering_jsp._jspService(system_002dclustering_jsp.java:115)     at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)     at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)     at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:530)     at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1216)     at com.opensymphony.module.sitemesh.filter.PageFilter.parsePage(PageFilter.java:118)     at com.opensymphony.module.sitemesh.filter.PageFilter.doFilter(PageFilter.java:52)     at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1187)     at org.jivesoftware.util.LocaleFilter.doFilter(LocaleFilter.java:74)     at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1187)     at org.jivesoftware.util.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:50)     at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1187)     at org.jivesoftware.admin.PluginFilter.doFilter(PluginFilter.java:78)     at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1187)     at org.jivesoftware.admin.AuthCheckFilter.doFilter(AuthCheckFilter.java:164)     at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1187)     at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:425)     at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:119)     at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:494)     at org.eclipse.jetty.server.session.SessionHandler.handle(SessionHandler.java:182)     at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:933)     at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:362)     at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:867)     at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:117)     at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:245)     at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:126)     at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:113)     at org.eclipse.jetty.server.Server.handle(Server.java:334)     at org.eclipse.jetty.server.HttpConnection.handleRequest(HttpConnection.java:559)     at org.eclipse.jetty.server.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:992)     at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:541)     at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:203)     at org.eclipse.jetty.server.HttpConnection.handle(HttpConnection.java:406)     at org.eclipse.jetty.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:462)     at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:436)     at java.lang.Thread.run(Thread.java:619)Caused by: java.lang.ClassNotFoundException: com.tangosol.net.Invocable     at java.net.URLClassLoader$1.run(URLClassLoader.java:202)     at java.security.AccessController.doPrivileged(Native Method)     at java.net.URLClassLoader.findClass(URLClassLoader.java:190)     at java.lang.ClassLoader.loadClass(ClassLoader.java:307)     at java.lang.ClassLoader.loadClass(ClassLoader.java:248)     ... 41 more