wicket atmosphere not updating the page

I am trying to use wicket-atmosphere (0.18) in wicket 6.12.0, on post,
subscribe method is getting called but any component I add to target is not
updating in the page, ajax debug window shows empty ajax-response, and
browser console has this error.

wicket/bookmarkable/resource/org.apache.wic…bstractDefaultAjaxBehavior/res/js/wicket-event-jquery-ver-1409764822476.js
404 (Not Found)

Please advice.