That's very weird. I used the file-checker like you wanted and it clearly showed them all to be down. I don't know what to do in the future then, I don't think I made any mistake now. FF said the files were removed due to content breaking their rules, I think. Did FF re-upload them again then?
I think they're trying to implement a system that blocks files for all but the uploaders if they match a certain hash. But this being FF, they can't get it done right and switch back-and-forth several times now.