The first part of which (and the part which triggers the error message) is Dutch for: part(ialy) translated. And followiong that are four definitely Dutch names.
Maybe you should grep through the sources (specialy* index.docbook*) to find that line. It could be possible that looking there you will see the obvious error and can repair it. Finding it or not, I think you should report upstream.
I removed the offending part and it built ok. I have already asked for help here. I will report to them. I guess there were no Dutch speakers over there.
Recocnising it as Dutch helped a bit, but reading the error message and then lookin in the mentioned file for the mentioned line is a primary reaction to such an error message IMHO.