Maybe you'll need a NoDvd patch or something, usually this "[1503]" means that. Try using some AlphaROM activators, one of them has to work, I had the same problem with another eroge and tried with all the Alpha activators until one worked, hope it works the same for you too.
Sorry if disturb, but can you please reupload this game? Thanks in advance.
https://www.anime-sharing.com/threads/✨shine✨-250123-アンクルおじ-フタナリ制服少女rpg~異世界からの侵略者~-ver1-06-rj01322235.1619486/