Code:
22:08:52.296 [script.err] [error] Script Error in mods/custom_campaign/data/export_descr_buildings.txt, at line 6138, column 2
Building DB error - culture db max settlement level differs from building db max settlement level for faction aztecs (bdg large_city vs clt huge_city)
22:08:52.312 [data.invalid] [error] Target building level not allowed: The Aztecs, village -> motte_and_bailey, core_building[0](wooden_pallisade) -> core_castle_building[1](wooden_castle)
22:08:52.312 [data.invalid] [error] Target building level not allowed: The Aztecs, town -> wooden_castle, core_building[0](wooden_pallisade) -> core_castle_building[1](wooden_castle)
22:08:52.312 [data.invalid] [error] Target building level not allowed: The Aztecs, large_town -> castle, core_building[0](wooden_pallisade) -> core_castle_building[1](wooden_castle)
22:08:52.312 [data.invalid] [error] Target building level not allowed: The Aztecs, large_town -> castle, core_building[1](wooden_wall) -> core_castle_building[2](castle)
22:08:52.312 [data.invalid] [error] Target building level not allowed: The Aztecs, motte_and_bailey -> village, convert_to_city[0](wooden_castle_to_village) -> convert_to_castle[0](village_to_wooden_castle)
22:08:52.312 [data.invalid] [error] Target building level not allowed: The Aztecs, wooden_castle -> town, convert_to_city[0](wooden_castle_to_village) -> convert_to_castle[0](village_to_wooden_castle)
22:08:52.312 [data.invalid] [error] Target building level not allowed: The Aztecs, wooden_castle -> town, convert_to_city[1](stone_keep_to_small_town) -> convert_to_castle[1](small_town_to_stone_keep)
22:08:52.312 [data.invalid] [error] Target building level not allowed: The Aztecs, castle -> large_town, convert_to_city[0](wooden_castle_to_village) -> convert_to_castle[0](village_to_wooden_castle)
22:08:52.312 [data.invalid] [error] Target building level not allowed: The Aztecs, castle -> large_town, convert_to_city[1](stone_keep_to_small_town) -> convert_to_castle[1](small_town_to_stone_keep)
22:08:52.312 [data.invalid] [error] Target building level not allowed: The Aztecs, castle -> large_town, convert_to_city[2](castle_to_large_town) -> convert_to_castle[2](large_town_to_castle)
22:08:52.312 [data.invalid] [error] Target building level not allowed: The Aztecs, fortress -> city, convert_to_city[0](wooden_castle_to_village) -> convert_to_castle[0](village_to_wooden_castle)
22:08:52.312 [data.invalid] [error] Target building level not allowed: The Aztecs, fortress -> city, convert_to_city[1](stone_keep_to_small_town) -> convert_to_castle[1](small_town_to_stone_keep)
22:08:52.312 [data.invalid] [error] Target building level not allowed: The Aztecs, fortress -> city, convert_to_city[2](castle_to_large_town) -> convert_to_castle[2](large_town_to_castle)
22:08:52.312 [data.invalid] [error] Target building level not allowed: The Aztecs, citadel -> city, convert_to_city[0](wooden_castle_to_village) -> convert_to_castle[0](village_to_wooden_castle)
22:08:52.312 [data.invalid] [error] Target building level not allowed: The Aztecs, citadel -> city, convert_to_city[1](stone_keep_to_small_town) -> convert_to_castle[1](small_town_to_stone_keep)
22:08:52.312 [data.invalid] [error] Target building level not allowed: The Aztecs, citadel -> city, convert_to_city[2](castle_to_large_town) -> convert_to_castle[2](large_town_to_castle)
That looks bad enough to me