If I were seriously pissed off with the PPRuNe coverage of my organization, I guess it would just be possible to inject some funny HTML or SQL code into a post on one of those threads which would either wreck the PPRuNe code or database, or cause the users browser to hang. In fact, if that funny code could be inserted in the title of the post, it would probably already cause problems if you try to load a forum page.
If I were a moderator or maintainer, the first thing I would do is look at the raw data that's being stored in the database entries in the relevant forum and threads, and look for anything that doesn't look like plain text.
Then again, I'm sure the same thing has occurred to the PPRuNe moderators and maintainers.
But it remains odd that the problems seem to be related to one forum only. And before that, to one or two threads only.