I can second this issue and it's been a few months. Batch downloads using EmuMovies in Launchbox, for lack of a better term, seem to be broken right now. I can confirm they work fine when you right click a game and select Edit --> Edit Metadata/Media and then hit the Download Media button within the Media tab in that dialog box. But batch downloading using Tools --> Download --> Update Metadata and Media for Selected Games (or all games) results in Launchbox giving me a bunch of 404 errors, usually for every single game.
Can the devs please address this particular issue? I'm on the latest version 13.22 for Windows.
Jared