@Harm: That is not the correct location to download the translations used by PivotX - the mo files. Those are available at http://pivotx.net/files/translations/
as the docs clearly state - see http://book.pivotx.net/page/3-9
@Lars: The reason not all languages are included is to keep the size of the PivotX zip file small. If there at some point becomes very many Danish PivotX users, we might include Danish by default.