Today I have encountered similar problems. For now it happens only on with the IR codes.

What is happening is this.
In a normal IR send, the busy LED on the RFX turns on a little before than the apropriate IR LED. This is normal operation.

Sometimes when I hit a random button with IR attached to it, all the RFX does is turn on the busy LED (no code is sent). The LED turns off after some time. The diagnostics.log registers a :
0450 Extender _IP_ didn't reply.

The XCF I use is an xcf I've used many times with the same settings. Also same router/access point, and a TSU9800, all the same as always. The only thing I can think is different is the bacth of the RFX9600 (it's a newer one). Something somewhere in he production went wrong?

EDIT: Please follow this thread: www.remotecentral.com/cgi-bin/mboard/prontopro/thread.cgi as it seems that the problems are linked.