Secondly, I followed your instructions - signed up as a beta tester - updated to 1.9.2 and it STILL does not work LOL
This has nothing to do with a version of Domotics Pad - if you are not getting the standard message notifications (not the Request Control Page ones), then your tablet is not making proper contact with the Google push server or else the devices are not paired properly. That is a standard Google text notification - nothing fancy there - and the plugin must be properly sending it to the Google server if you aren't seeing errors in the log. Unfortunately, Google won't tell the sending app whether or not the push is successful or even can be sent.
Can you send me the device registration ID for the tablet (in properties of the device)? Can send via PM if concerned about in public. I can check the server logs and see if they yield any clues.
I guess you get what you pay for... Indigo is a nice idea, but requires jumping through hoops to do almost anything
That is almost the complete opposite of most people's experience, fwiw. I'll give you, getting a Kindle Fire up and running as a tablet controller is more involved and could be considered jumping through hoops, but that is not exactly a supported platform. We do our best to give support and help with it, but it is limited in feedback and official Google support. MANY people have gotten this up and running with ease, though, so the end goal is definitely attainable.
I would focus on getting the basic notification going as that is the simplest operation that is not working. I'd say checking the server, as mentioned above, is probably our best shot.