It's a place to start. Given that I don't use a Mac (and most people here don't), it's the best I can do. Unless you want me to do all the research for you. You could also try searching the thread here for advice.
Also, you don't need RPG Maker itself. That's for developers. It's my understanding that RPG Maker uses some function calls that are unique to Windows, making porting it to other systems tricky. Most of the advice I've seen involves using an emulator.
The message says you don't have regionals.dat file in the Data folder. Is that true? You should, it's included in the archive. Did something go wrong with the extraction? Did you only extract Game.exe?