I guess, there is a problem with your Jersey servlet. Plz check your web.xml . Compare it with my one in attachment. I havn't deployed it yet on any enterprise containers, cause my idea was to use something lightweight, until there is no leak of functionality.
P.S. by the way dont forget to update from repository. And now it is a maven project, so you can simply type mvn clean package tomcat:deploy to deploy it on your tomcat server (I assume, that you already added you tomcat manager to maven settings.xml), so why not to deploy jbpm + rest wrapper as a standalone server?
P.P.S. There is a lot of new features not yet described in wiki article. I hope to rebuild it soon. Check /jbpm-rest/application.wadl for the full list.