The problem is that iRex has changed the interfaces that the plugin has to work with, but has not released the source code yet. Until they do, the only way to find out what has changed is by reverse engineering the binaries, which is tedious, and probably not worth the trouble.
Matthijs (iRex developer) has said in another thread that the changes are only small, so it should be easy to get it working again once the source code is available. So please have a little patience
(I don't have anything to do with the CBZ plugin, but I have written the DjVu plugin, which has exactly the same problem)