this is a message for a developer of this great plugin, mr. Hiroaki. Sorry, I didn't find other way how to contact you since I don't speak Japanese :).
Anyway... I translated your plugin into Czech language, so I'd like to send you those files. If you could add them to the release, it would be wonderful.
There is a bug in CFT - when using Multiple fieldsets and TinyMCE on textarea, clicking Add new will not add TinyMCE correctly on the new textarea.
I have fixed this issue - I have changed only the line 2099 (CFT version 1.8.1). It's still line 2099 in 1.8.3.
I hope it will be useful for you...
Thanks a lot, Jakub