As far as we can see, it is an issue with the forum software.
In short, his registered name is "Dr deAth", without the apostrophe (probably removed automatically on registration). This is the name address that should be added to the recipient field of the PM assistant, but it seems to grab the display name (with the apostrophe).
Our tech has been working on it for some time, but apparently there is no easy solution for it, other than the pretentious chap dropping the oh-so-fancy apostrophe from his display name.
