Registering this property is the very first thing the add-on does. I don't know how you got so far without it having actually worked.

You can download an older version of the tools from this page.[steamreview.org]

I'm not very interested in supporting leaked model sources. They may just be broken.

I managed to download the file. It's exactly like I told you. Two items have shape keys: "body" and "ZHANNA". So you get two VTA files, which is the correct outcome.

I don't see the point in doing this when I already host the add-on on a dedicated website, and have an updater. Going to that site and waiting for someone else to approve such a large add-on would be a drag.

What I could do is host an extension repository[docs.blender.org] and replace the current add-on updater with that.

You need to use a more recent version of Blender.

Where can I find these files?

That download has also expired. Please use a better upload service.

The download has expired.

OK, upload your blend file and I'll have a look.