This week's book giveaway is in the OCMJEA forum. We're giving away four copies of OCM Java EE 6 Enterprise Architect Exam Guide and have Paul Allen & Joseph Bambara on-line! See this thread for details.
The NPE is occurring in a class that is not provided by JBoss AS. Is com.gtnet.pk.nav.ProcessTree your class? If so, you need to find out why it is getting a NPE in the constructor. If it is not your class, you need to ask the person who wrote it, or get the source code for it.