Anata no Shiranai Kangofu ~Seiteki Byoutou 24 Ji~Forum

I have installed the game according to the instructions, have already set the locale to Japanese beforehand.
However, when I try to run the game I get the following error in the picture:
I can speak decent Japanese so I tried searching Japanese sites, but there were no helpful results at all.
My PC has Windows 10.
Thank you!