Videos not showing up in library

I have an issue that’s a real head-scratcher for me. I have a set of videos, the six episodes of the BBC’s Hitchhiker’s Guide to the Galaxy, as six separate xvid (.avi) files. They show up when I navigate to Videos -> Files -> source of these files, and they play quite nicely. But when I try to add them to the library, they either don’t show up properly, or they don’t show up at all.

Here’s the details:
I had these files in a folder within the path set for Movies, so, for example videos/movies/Hitchhiker’s Guide to the Galaxy. In this folder, the files were named “Episode 1.avi”, “Episode 2.avi”, … , “Episode 6.avi”.
In the Movies library, they showed up as different random movie titles (the files’ metadata are blank). Selecting one would play a HHGG episode.

I renamed the files, “Hitchhiker’s Guide to the Galaxy – Episode 1.avi” and so forth.

I refreshed the library, the old entries remained, but no new entries were added. Clicking on one of the old entries gave me the Couldn’t be found dialog with the option to remove from the library. I’d click Yes to each of the old entries, and they’d be gone from the library. Refreshed the library again. Old entries remained gone, but the renamed files still didn’t show up.

Renamed the files back to their original filenames (“Episode 1.avi”, etc.), refreshed the library, and all the old, wrong entries came back.

So then I created a new folder, videos/TV/, and moved the entire HHGG directory and its files into it, then pointed empty TV Shows library to it. I had it add files to the library.

Now, when I go to the TV Shows library, the shows’ genres and studios information are listed, and in the Title list, a single entry:
“Hitchhiker’s Guide to the Galaxy 0/0”
Clicking on that gives me an empty list.

Again, I can get to these episodes by navigating through Videos -> Files -> source of the files, but they don’t show up in the library.

Is this a bug? Or am I doing something really wrong here?