Is anyone still experiencing this error?

Those are the legacy shops. We recently changed to a new system and so you need to create new shops. You can still get to your own individual shops to move things but you can't put anything new in those and you cannot reprice anything. So create a new shop and you should be good to go!

New Shop Guides

There is more about the new shops on that topic.

Locking this up since this issue is fixed :D