Never mind, I just fixed it. Seems I was trying to run the game directly, bypassing the bootmenu. OP, you should make sure you're running bootmenu.exe and not grisaia.exe; that fixed the problem for me.
Hi there, I actually made an account here because I've been getting the same exact error on Windows 7. My directx is fully updated (on 9 and 10 at least), and so is my GPU. I have no idea what would be causing it to fail.