Error in running Mainframe.java

[NivedhaKHJ]

when i run Mainframe.java, i get the following error :

java.lang.ClassNotFoundException: com.thoughtworks.xstream.XStream
at java.net.URLClassLoader$1.run(Unknown Source)
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 weka.core.xml.XStream.read(XStream.java:253)
at main.java.edu.lipreading.Utils.getTrainingSetFromZip(Utils.java:152)
at main.java.edu.lipreading.TrainingSet.get(TrainingSet.java:29)
at main.java.edu.lipreading.gui.TrainingPanel.(TrainingPanel.java:89)
at main.java.edu.lipreading.gui.MainFrame.(MainFrame.java:109)
at main.java.edu.lipreading.gui.MainFrame$1.run(MainFrame.java:41)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$200(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
java.lang.NullPointerException
at main.java.edu.lipreading.gui.TrainingPanel.(TrainingPanel.java:89)
at main.java.edu.lipreading.gui.MainFrame.(MainFrame.java:109)
at main.java.edu.lipreading.gui.MainFrame$1.run(MainFrame.java:41)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$200(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
Exception while removing reference: java.lang.InterruptedException
java.lang.InterruptedException
at java.lang.Object.wait(Native Method)
at java.lang.ref.ReferenceQueue.remove(Unknown Source)
at java.lang.ref.ReferenceQueue.remove(Unknown Source)
at sun.java2d.Disposer.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

The error is in the line :

Sample read = (Sample) XStream.read(samplesZip.getInputStream(entries.nextElement()));

I have included weka3.7.3 jar. But i don't know how to correct it.
Please guide me