The Zone Controller has a debug stream built into it that is very useful for pinpointing problems.
You can access the Debug information using the Bye Bye Standby viewer, which can be downloaded from the technical forum at www.ByeByeStandby.com/forum
Technical note: debug information from the Zone Controller is sent as a UDP broadcase message from the controller to addresses 255.255.255.255 over port 53007 - any UDP client should be able to see the debug stream.