Lust Doll Plus > www > img > faces
That specific folder is where it needs to go.
Also make sure the dummy file is named "p-zbrow1" and its file type is ".png"
Not ".jpg" or ".img" or even ".rpgmvp"
As an aside, this bug is caused by the game trying to load a save that used a file the game itself no longer needs. This also means there's an almost 100% chance lots more bugs are going to show up for similar reasons. To avoid this, it's highly recommended to start a New Game+ so your character can be re-built with up-to-date file information.
You'll be able to keep your stats, items, skills, clothes, and money, so at least it will take much less time to get back to where you were.
