This is not a filename, but it is the identical text that I have used for an episode plot for this TV-series disc.
The only images except for the episode images are the front & back cover and a backdrop image.
What if you go to that entry in your collection, edit it, then find it there, what does it say there? Maybe you can fix it there manually?
Found it now. I had pasted the plot text of one episode into the image url field of another episode.
Ah, that would explain it 
good to hear that you were able to fix it!