Anand,
You still need to make sure all the jars that are needed are on the application classpath. In this case, it's not able to find javax.persistence.Persistence, so that means the jar containing the jpa classes is not in the tomcat lib dir (or the lib dir of the jbpm console server war). Simply adding the jar in one of those two locations should probably solve this (and you probably need quite a few others as well).
Kris