Have you tried listening to the _RV.ERROR.>
and _RV.WARN.>
subjects? You need to subscribe on each transport connected, and also the interprocess transport to get non-transport specific errors. This is all described in the "Advisory Messages" section of the RV manual. To whet your appetite
Rendezvous software presents asynchronous advisory messages to Rendezvous programs. Advisory messages indicate errors, warnings and other information.
In contrast with status codes (which indicate success or failure within a specific Rendezvous call), asynchronous advisory messages notify programs of events that occur outside of the program’s direct flow of control—for example, the program is processing inbound messages too slowly, causing the daemon’s message queue to overflow.
Fair warning, I am working with version 7.3, so things may have changed a bit in new versions.