Sorry, but there's a lot of talking here, and I'm missing the point.
Someone has taken the effort to translate the english laguage file to dutch, packed it, zipped it and all.
It doesn't seem to work however.
If the job isn't done properly, and there is a lot of work, that's another thing. But I assume this is a 15 minute job, improving the usability of the plugin.
Unfortuneately I can't program, so can't do it myself.
Anyway, either the instructions aren't clear, or there is a minor problem or misunderstanding to be sorted out.
Please take the time to fix this, so others (and myself) can take advantage of the work jos has done. thanx