If you are running Weka and get an error when trying to run the LibSVM classifier, try adding the libsvm.jar file to your jar path:
java -classpath $CLASSPATH:weka.jar:libsvm.jar weka.gui.GUIChooser
For me this looks more like:
java -classpath /usr/sness/weka-3-5-7/weka.jar:/usr/sness/WLSVM/lib/libsvm.jar weka.gui.GUIChooser
LibSVM and Weka
ntegrating LibSVM into Weka Environment