There was a major bug in languages when Greg released w1.5 and w1.4.4. Unfortunately because it was in w1.4.4 it appeared in kiwitrees as well.
I have since corrected the files. You can either wait for the next release of the full code later this week, or try these two steps:
- Download and install the latest complete set of language files from http://kiwitrees.net/services/simpl-add-ons/download-info/language-zip/ The latest is dated 27 Nov 2013.
- Replace the file /library/WT/I18N.php with the one in the zip folder attached here.