Request for user manuals in doc or html (text) format (to make machine translation easier)
I do not speak Japanese but this looks like a great piece of software. I was able to get it to work without documentation but it took alot of playing around and guesswork. Perhaps you could make the user manuals in PDF available in a non-pdf format so that users can machine translate them into their own language. A single html page on a web server would be easiest. This level of translation is often sufficient to understand user docs. I was able to read the wiki entries using the machine translation built into the Chome browser and that was very helpful.
Also, some of your error messages are still in Japanese. Maybe you could check that.