well, i tried to visit an old thread that i linked to in a post a day before, and found this message:
[#103137] You do not have permission to view this topic.
does this mean it was deleted?

Most probably. I don't know much about the codes, but if it's simply not available, then it might have been deleted. Try looking for the thread manually if you can, if it's still not there, it's most likely been deleted.

The thread was, most likely, thrown into the fires of Mt. Doom by a moderator/admin.

It must have been moved. Chances are that it is now somewhere in the "moderators only" forum where they dispose of threads that have been locked or removed.

Yes, it was deleted. It's in the Trash forum, which only mods and admins have access to.

Is that a real thing? Please please please post a screenshot of it's front page. Please? :3

One does not simply 'view' the trash fourm.