If you can load other add-ons with your Educational License (which I am pretty sure you can), but you can't load your add-on, then I would suspect a problem with the compilation of the add-on.
Don't ask me what though.
Someone that develops add-ons will have to answer.
I think you have to be registered as a developer?
But I am really not sure as I don't develop add-ons myself.
Anyone can develop an add-on that works in the demo version... the easiest way to learn. For an add-on to work in any licensed version, the developer must be registered with Graphisoft and received a personal MDID to identify themselves within the add-on. All of this is explained both in posts in this forum, and in the Archicad API documentation. You can learn by compiling any of the many sample add-ons provided with the API dev kit... which will work in demo mode (without the MDID).