A recent update caused avatars in offline testing mode to break, which would instead give the "ERROR" robot when the world loads. A later patch partly fixed this as your uploaded avatars and those from the "public" section of the avatar list will load, however cached avatars will still not be able to load as of now. Those dang ERROR robots don't even work with the world, and if you stand on a pad while pressing Start, it'll just go to using an NPC for the dance.
This sucks.