I see, is the Date/time format also set to japanese? That is Control Panel - Region - Format tab? If both the Format and Administrative tab were set to japanese when you installed the game.. then I'm not sure what is the problem.
As far as I know, Atelier Kaguya games need to be installed and played with your computer system and date set to japan locale. Otherwise it would have that error and not run. Try reinstalling after switching your system to Jap local with jap date/time?