Argh, I thought I removed everything involving the RTP for this one. You can get the RTP for 2003 here and then it should run properly. Rpgmaker is weird where you have to scrub EVERYTHING from the database to not get the RTP needed error, which is dumb because nothing that appears in this game is RTP. Sorry for the issue!
Edit: By the way, the RTP is all the default graphics, sound effects, and music. Every new project comes with all of those auto selected for characters, menu sound effects, enemies, etc. The way rpgmaker works is that if someone uses the rtp, they can extract without it and save space so that anyone who has the rtp installed on their computer can play it. I'm not sure if I explained this right but it's convenient if you play a lot of rpgmaker games.