No, I don't think that's it. I've been messing with it, and if i don't run it in Applocale, it will actually run the installer, but it won't get further than 44% before stopping and giving me the same error. I checked, and it doesn't look like the directory files are in japanese...
I think all i need to do is get the RTP2000 installed, and i can just play the game, but I can't seem to manage to do that. I've looked around and I'm not the only one with this problem, but when I try solutions that worked for others, it doesn't work for me.