Unknown Error in Cluster Control Panel menu - UConsole

We have configured an Ultra ESB cluster successfully. In uconsole, we can see all nodes in the cluster under cluster navigator menu. However, when we tried "Cluster Mgmt > Control Panel" menu, we got a error box saying, "Unknown error - Try to login again". In the logs, it is a Null Pointer exception.

ERROR ProxyServiceAdmin java.lang.NullPointerException at org.adroitlogic.ultraesb.clustering.GlobalMetricsStreamRegistrar.resolveLocalToGlobal(GlobalMetricsStreamRegistrar.java:67) at org.adroitlogic.ultraesb.clustering.ClusterManager.resolveGlobalStream(ClusterManager.java:859) at org.adroitlogic.ultraesb.core.config.AbstractConfigurationElement.resolveMetricsStreams(AbstractConfigurationElement.java:266) at org.adroitlogic.ultraesb.core.ProxyService.toDetailedView(ProxyService.java:596) at org.adroitlogic.ultraesb.core.mgt.ProxyServiceManagement.getProxyServices(ProxyServiceManagement.java:79) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:601) at com.sun.jmx.mbeanserver.ConvertingMethod.invokeWithOpenReturn(ConvertingMethod.java:192) at com.sun.jmx.mbeanserver.ConvertingMethod.invokeWithOpenReturn(ConvertingMethod.java:174) at com.sun.jmx.mbeanserver.MXBeanIntrospector.invokeM2(MXBeanIntrospector.java:117) at com.sun.jmx.mbeanserver.MXBeanIntrospector.invokeM2(MXBeanIntrospector.java:54) at com.sun.jmx.mbeanserver.MBeanIntrospector.invokeM(MBeanIntrospector.java:235) at com.sun.jmx.mbeanserver.PerInterface.getAttribute(PerInterface.java:83) at com.sun.jmx.mbeanserver.MBeanSupport.getAttribute(MBeanSupport.java:206) at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.getAttribute(DefaultMBeanServerInterceptor.java:647) at com.sun.jmx.mbeanserver.JmxMBeanServer.getAttribute(JmxMBeanServer.java:669) at javax.management.remote.rmi.RMIConnectionImpl.doOperation(RMIConnectionImpl.java:1463) at javax.management.remote.rmi.RMIConnectionImpl.access$300(RMIConnectionImpl.java:96) at javax.management.remote.rmi.RMIConnectionImpl$PrivilegedOperation.run(RMIConnectionImpl.java:1327) at javax.management.remote.rmi.RMIConnectionImpl.doPrivilegedOperation(RMIConnectionImpl.java:1419) at javax.management.remote.rmi.RMIConnectionImpl.getAttribute(RMIConnectionImpl.java:656) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:601) at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:322) at sun.rmi.transport.Transport$1.run(Transport.java:177) at sun.rmi.transport.Transport$1.run(Transport.java:174) at java.security.AccessController.doPrivileged(Native Method) at sun.rmi.transport.Transport.serviceCall(Transport.java:173) at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:553) at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:808) at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:667) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) at java.lang.Thread.run(Thread.java:722)