Oh yeah... I was experiment with Avitab, and I left in the code a requirement to have the Avitab installed. For now you must have installed it to work. You can get it from here:
https://forums.x-plane.org/index.php?/files/file/44825-avitab-vr-compatible-tablet-with-pdf-viewer-moving-maps-and-more/
A fix is coming "soon", with a few additions.