I think I tracked down that problem; when the mod was installed together with the sound pack, there were issues with the new mod's mainmenu soundtrack having a different tag in audio xmls, plus a mismatch with an earlier version of CivEraInfos using the ERA_INDUSTRIAL tag. I fixed those and made a patch combining that fix with the Fall Further Themes error fix, a trackname fix (bug #NH3), and Events to spawn missionaries with religion tech discovery (will need to add civ-specific python once the Civs XML is done.) So I'll attach all that and you can upload it as a Patch A to replace the Quickfix. (Make a note that the patch should be applied after the soundpack not vice versa.)