Found out how to reproduce the problem.
If the plugin isn’t in a sub folder in the Plugins folder (IE: Plugins/AdvancedSessions) then the engine doesn’t correctly package it. The last release I forgot to move all of the files into a folder prior to zipping them. I have never tried to use it without a sub folder so I couldn’t re-produce it originally but finally it dawned on me that it was the only thing I hadn’t checked on yet.
I updated the download for new users and for everyone else just make a new “AdvancedSessions” folder and move the files into it and everything should work fine. I’ll add a reminder in the installation steps to check that they are in a sub folder already.