Glad you figured something out.Hey, just wanna let you know I fixed it. I'm not certain which part of this worked, but I ensured the folder LonaRPG was in was not set to read-only and ran the MTL app as admin. I figure something about the file permissions wasn't allowing the tool to overwrite the language files.
I personally use dedicated drives for games, so I very rarely get permissions issues with games/tools. (They are formatted to NTFS and using default permissions)
I doubt it was anything to do with the folder having read-only set, that doesn't function with folders the same way as it does with files.
Running the MTL tool as admin probably worked around the issue you were having (which likely would of been a permissions thing)