This a bug report which should go in the bug tracker.
There you can tell us what Moodle version you are using etc.
Martin Dougiamas
Posts made by Martin Dougiamas
Linking to local files is widely considered to be a security hazard so the browsers are all dropping it. Pity.
No, no, don't set their language to _local ... it's used automatically and never appears in the menus for selection by users.
If your setting is "ja_utf8" then "ja_utf8_local" will be checked first AUTOMATICALLY.
If your setting is "ja_utf8" then "ja_utf8_local" will be checked first AUTOMATICALLY.
Since you seem to be supporting Dialogue (I'm not!) then you probably should write those UTF migration scripts! 
http://docs.moodle.org/en/UTF-8_contrib
http://docs.moodle.org/en/UTF-8_contrib
I'm not sure what happens if you try and run it again (I'll get Yu to respond to that), but if you are installing a module new into an already-UTF Moodle 1.6 then you don't need to convert anything (there is no data yet).