KMail is irretrievably broken

Hello list,

I've finally had to admit defeat. I cannot get KMail-2 to import my old 
messages, either from a KMail archive or from the corresponding directory 
structure. I created the directory by extracting the archive using Ark.

I'm running Gentoo Linux, updated daily and backed up weekly. Many's the 
time I've created a new home directory for myself, arranged KDE-plasma the 
way I like it and tried to import the old messages into KMail. I've taken 
great pains to avoid doing two things at once, or going too fast, and I've 
rebooted at every sign of trouble.

The only conclusion I can come to is that there are some damaged messages in 
the archive, such that KMail cannot handle them. But instead of being 
programmed defensively, KMail seems to assume blithely that every field is 
properly formatted. When it finds something that isn't, it throws a wobbler.

Thinking that I might be doing something wrong in Gentoo, I even went to the 
trouble of installing the latest version of OpenSuse. I got the same thing 
again. In particular, numerous duplicates being created without any access 
to the Internet. When I say "numerous," I mean scores of duplicates of each 
of a dozen or more separate messages in various folders. It's chaos.

The only thing I can do now is to start a fresh message collection, leaving 
the archive for searching with text tools.

Somebody has let the side down, and badly.

-- 
Regards,
Peter.