So I finally found a solution to the NotFoundError
NotFoundError: The operation failed because the requested database object could not be found. For example, an object store did not exist but was being opened.
So after doing some more digging on google, it turns out the error resided in my local storage folders.
So I went to (user)\AppData\Roaming\Mozilla\Firefox\Profiles\(profile)\storage\default
and I moved http+++uploads.ungrounded.net to my desktop, and it automatically recreates itself, and voila! I'm not getting that error anymore.
That's an ENORMOUS hurdle out of my way, I'm actually now motivated to continue developing 3D games for ng, now that I have this albatross off my neck!