The showSubscriptionTable() method in the SubscriptionManager.java does not expect null FilterType object, thus raising NullPointerException:

org.jboss.ws.extensions.eventing.mgmt.SubscriptionManager.java
460: pw.println("<tr><td>" + s.getIdentifier() + "</td><td>" + s.getExpires() + "</td><td>" + s.getFilter().getExpression() + "</td></tr>");

the snippet:
s.getFilter().getExpression()

should be:
((s.getFilter() != null)?s.getFilter().getExpression():"")
or something like that.