Edit: I have tried to install Thunderbird, Eudora, and PegasusMail, and import the offending DBX, but it still only gives me the 93 remaining e-mails in the folder, not the several hundred that are inaccessible.
P.S. If you are experiencing that clicking on an entry on your friendspage, leads you to a page saying something like "404 not found", here's the explanation (and if it 404s you, go back and click on the link again). In short, there was a problem that people were unable to access communities on LJ if the link they followed didn't have a trailing slash. They have "fixed" this, but in the process created the error that when one is going to a livejournal one hasn't visited before, an extra slash is inserted into the URL. The second time one goes there, one has of course visited there before, so the cookie is set, and one doesn't get the extra slash. So for now, the solution is to go back and click again.