If were stuck with the error, would going back and crafting the silk one then let us change again?
Viewing post in Pokémon Naughty version comments
Update: Yes, going back to craft the night gown fixes the issue. The game sets it in the third slot of your wardrobe, which is what the game seems to always expect to be there, therefore breaking if anything else is there.
At least your save isn't perma-fucked, but I'm still surprised the dev never thought of this happening.