That is indeed strange. But try installing the game through the Itch app. If it's a permission-related error, then installing the game that way should fix it.
No longer an issue since I just got my first new Mac in eight years. M1 Max chip, and somehow it actually runs this game smoothly. A bit crashy, but it loads. Is this version of RPGMaker 64bit? It has to be for this to be running even under Rosetta2 emulation.
