Drat. I really need to do some more testing, then... Here's one thing you might try (if you're willing) -- I'm storing persistent data for Pierogi in the standard Qt manner, in a file in your home directory called ".config/pietrzak.org/Pierogi.conf". It may be that that file has been corrupted in some manner; you could, say, move it to "Pierogi.conf.backup" to force Pierogi to start fresh with a new config file, and see if the errors continue. (The config file is almost readable, if you're interested in seeing what Pierogi is trying to store. )
Yeah, my error handling mechanism is really bad right now. Yet another piece of Pierogi that needs a lot more work...
Oh! Hey! Let me know which if the Strong keysets are working -- both Strong and Triax are using the classic NEC protocols, so if Strong keys are doing something on the Triax machine, that means that both devices are using the same NEC "device number". All I would need to do, I think, is graft the device number Strong is using onto the command list Triax is using, and we might be able to come up with a usable keyset!