It does absolutely nothing (hangs) when I enter the (properly spelled) filename and hit enter. Which, I believe, is the same thing that happens with a misspelled filename.
I'm pretty sure I've also edited the file with at least one of jce3000gt's tools, and yousei's map editor, but this wasn't a problem for previous editions of ff4kster (like I said, my older ff4kster version still works for this hack).
Anyway, it doesn'treally matter. I've decided to start fresh with a clean ROM for other reasons anyway. Figuring out why this is happening would really only serve to satisfy my curiosity, and I'm sure you have higher priorities than that.