So I was tinkering around with the code, and when I tried to take the basic step of setting COMPRESSED = FALSE, the error below prevented me from playing the game. I got around this by simply removing the lines that made the game draw from rvdata2 for the most part. I went on to try and modify monster behavior, when I noticed that the game was drawing the data from the compressed file MonsterLib.rvdata2, and this is what was causing the error before, because unlike the other parts of the game (weapons, items, etc), the code for monsters in FileGetter doesn't have a secondary line telling it what to do if the file wasn't compressed, and this was what was causing the error below . Since I'm not at all experienced in RPGMaker, I apologize if the error is the result of some basic mistake on my part, and would like some help to solve it.