It means the creator forgot to upload the correct stand alone version of the game. What a dunce. Try downloading it again it should work. If using Firefox, you may need to clear the cache for the newest uploaded version. Remember, when playing the game, press F4 for windowed mode. If you want a good looking font, and don't have RPG Maker 2000(3) you'll need the rm2k3 fonts. I suggest Google, as I think posting a link to them is considered a no no here.