Hi ssampath, that is some pretty old documentation you are following. If you are just starting off with jBPM you should definitely use the latest version, jBPM 5.1.0. Here are some helpful links to get you started:
(project page) http://www.jboss.org/jbpm
(docs) http://docs.jboss.org/jbpm/v5.1/userguide/
(blogs) http://kverlaen.blogspot.com/ and http://blog.athico.com/
(presentations, search for jbpm) http://www.jboss.org/drools/presentations
Hope this helps.