I am getting error in console but I try to fix using by webchat

2015.05.09 16:51:42 org.jivesoftware.openfire.container.PluginManager - Error loading plugin: /usr/share/openfire/plugins/webchat

java.lang.NoClassDefFoundError: org/mortbay/jetty/servlet/Context

at java.lang.Class.getDeclaredConstructors0(Native Method)

at java.lang.Class.privateGetDeclaredConstructors(Class.java:2585)

at java.lang.Class.getConstructor0(Class.java:2885)

at java.lang.Class.newInstance(Class.java:350)

at org.jivesoftware.openfire.container.PluginManager.loadPlugin(PluginManager.java :414)

at org.jivesoftware.openfire.container.PluginManager.access$300(PluginManager.java :76)

at org.jivesoftware.openfire.container.PluginManager$PluginMonitor.run(PluginManag er.java:1068)

at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)

at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:304)

at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301 (ScheduledThreadPoolExecutor.java:178)

at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(Schedu ledThreadPoolExecutor.java:293)

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:745)

Caused by: java.lang.ClassNotFoundException: org.mortbay.jetty.servlet.Context

at java.net.URLClassLoader$1.run(URLClassLoader.java:366)

at java.net.URLClassLoader$1.run(URLClassLoader.java:355)

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

at java.net.URLClassLoader.findClass(URLClassLoader.java:354)

at java.lang.ClassLoader.loadClass(ClassLoader.java:425)

at java.lang.ClassLoader.loadClass(ClassLoader.java:358)

… 14 more

2015.05.09 16:52:02 org.jivesoftware.openfire.container.PluginManager - Error loading plugin: /usr/share/openfire/plugins/webchat

java.lang.NoClassDefFoundError: org/mortbay/jetty/servlet/Context

at java.lang.Class.getDeclaredConstructors0(Native Method)

at java.lang.Class.privateGetDeclaredConstructors(Class.java:2585)

at java.lang.Class.getConstructor0(Class.java:2885)

at java.lang.Class.newInstance(Class.java:350)

at org.jivesoftware.openfire.container.PluginManager.loadPlugin(PluginManager.java :414)

at org.jivesoftware.openfire.container.PluginManager.access$300(PluginManager.java :76)

at org.jivesoftware.openfire.container.PluginManager$PluginMonitor.run(PluginManag er.java:1068)

at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)

at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:304)

at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301 (ScheduledThreadPoolExecutor.java:178)

at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(Schedu ledThreadPoolExecutor.java:293)

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:745)

Caused by: java.lang.ClassNotFoundException: org.mortbay.jetty.servlet.Context

at java.net.URLClassLoader$1.run(URLClassLoader.java:366)

at java.net.URLClassLoader$1.run(URLClassLoader.java:355)

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

at java.net.URLClassLoader.findClass(URLClassLoader.java:354)

at java.lang.ClassLoader.loadClass(ClassLoader.java:425)

at java.lang.ClassLoader.loadClass(ClassLoader.java:358)

… 14 more