Let's Go to the City.
Vooks' Daniel Vuckovic attempted to use the DS Suitcase to transfer his Wild World catalog and character to the new game. Instead of a catalog loaded with playroom furniture and Mario accessories, he was presented with this error message, as well as a similar one on the DS.
This is significant for two reasons that we can think of: first, it's definitive proof that the DS Suitcase is region-locked. If your copy of Wild World is imported, the gates to your Wii town are firmly closed. Second, it means that Animal Crossing: Let's Go to the City is basically missing a feature in Australia. Nintendo is just having terrible luck with this DS Suitcase thing!