it always shows this message

Starting Client Control Plugin

Starting Fastpath Server

log4j:ERROR Could not instantiate class [net.sf.kraken.util.Log4JToOpenfireAppender].

java.lang.ClassNotFoundException: net.sf.kraken.util.Log4JToOpenfireAppender

    at java.net.URLClassLoader$1.run(Unknown Source)

    at java.security.AccessController.doPrivileged(Native Method)

    at java.net.URLClassLoader.findClass(Unknown Source)

    at java.lang.ClassLoader.loadClass(Unknown Source)

    at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)

    at java.lang.ClassLoader.loadClass(Unknown Source)

    at java.lang.Class.forName0(Native Method)

    at java.lang.Class.forName(Unknown Source)

    at org.apache.log4j.helpers.Loader.loadClass(Loader.java:179)

    at org.apache.log4j.helpers.OptionConverter.instantiateByClassName(OptionConverter .java:320)

    at org.apache.log4j.helpers.OptionConverter.instantiateByKey(OptionConverter.java: 121)

    at org.apache.log4j.PropertyConfigurator.parseAppender(PropertyConfigurator.java:6 64)

    at org.apache.log4j.PropertyConfigurator.parseCategory(PropertyConfigurator.java:6 47)

    at org.apache.log4j.PropertyConfigurator.configureRootCategory(PropertyConfigurato r.java:544)

    at org.apache.log4j.PropertyConfigurator.doConfigure(PropertyConfigurator.java:440 )

    at org.apache.log4j.PropertyConfigurator.configure(PropertyConfigurator.java:367)

    at net.sf.kraken.KrakenPlugin.setLoggerProperty(KrakenPlugin.java:284)

    at net.sf.kraken.KrakenPlugin.<init>(KrakenPlugin.java:61)

    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)

    at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)

    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)

    at java.lang.reflect.Constructor.newInstance(Unknown Source)

    at java.lang.Class.newInstance0(Unknown Source)

    at java.lang.Class.newInstance(Unknown Source)

    at org.jivesoftware.openfire.container.PluginManager.loadPlugin(PluginManager.java :420)

    at org.jivesoftware.openfire.container.PluginManager.access$300(PluginManager.java :80)

    at org.jivesoftware.openfire.container.PluginManager$PluginMonitor.run(PluginManag er.java:1067)

    at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)

    at java.util.concurrent.FutureTask$Sync.innerRunAndReset(Unknown Source)

    at java.util.concurrent.FutureTask.runAndReset(Unknown Source)

    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$101 (Unknown Source)

    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.runPeriodi c(Unknown Source)

    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(Unknow n Source)

    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)

    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)

    at java.lang.Thread.run(Unknown Source)

log4j:ERROR Could not instantiate appender named "openfire".

log4j:WARN No appenders could be found for logger (org.jivesoftware.util.log.util.CommonsLogFactory).

log4j:WARN Please initialize the log4j system properly.