Have you uninstalled the previous miniclient before installing the new one?

If you did and you get the same error with the new version, try to clear the cache with the game doctor function in the miniclient.

I use the version 2.4.0.12121 of the miniclient and have no problem as well, you may try to download this version and see if it works for you.

Here you can download it, I hope it helps: http://naruto.oasgames.com/en/articlelist/all/new_miniclient