Can it be that I don't have all DLCs - and perhaps your mod wants them...?
I am no modder, but for instance, I read
here an example:
"The Foreign Key it can't find is the DLC civs. Creator should have used WHERE EXISTS tags like they did for modded civs. I'll let them know of the issue and hope they can patch it quick."
here is the log:
[3577146.625] [Localization]: StartupErrorMessages.xml
[3577146.625] [Localization]: Input XML does not contain database entry tags. GameData, GameInfo or Database
[3577150.373] [Localization]: Validating Foreign Key Constraints...
[3577150.375] [Localization]: Passed Validation.
[3577150.395] [Configuration]: Validating Foreign Key Constraints...
[3577150.395] [Configuration]: Passed Validation.
[3577158.272] [FullTextSearch]: Initializing FullTextSearch
[3577159.041] [Gameplay]: Validating Foreign Key Constraints...
[3577159.061] [Gameplay]: Passed Validation.
[3577161.203] [Configuration]: Validating Foreign Key Constraints...
[3577161.203] [Configuration]: Passed Validation.
[3577162.286] [FullTextSearch]: FTS - Creating Context
[3577245.788] [FullTextSearch]: FTS - Creating Context
[3577252.719] [Configuration]: Validating Foreign Key Constraints...
[3577252.719] [Configuration]: Passed Validation.
[3577258.805] [Configuration]: Validating Foreign Key Constraints...
[3577258.806] [Configuration]: Passed Validation.
[3577271.912] [Gameplay] ERROR: FOREIGN KEY constraint failed
[3577271.912] [Gameplay] ERROR: FOREIGN KEY constraint failed
[3577271.912] [Gameplay]: Validating Foreign Key Constraints...
[3577271.917] [Gameplay] ERROR: Invalid Reference on BuildingModifiers.BuildingType - "BUILDING_TLACHTLI" does not exist in Buildings
[3577271.917] [Gameplay] ERROR: Invalid Reference on BuildingModifiers.BuildingType - "BUILDING_PRASAT" does not exist in Buildings
[3577271.917] [Gameplay] ERROR: Invalid Reference on BuildingModifiers.BuildingType - "BUILDING_BASILIKOI_PAIDES" does not exist in Buildings
[3577271.917] [Gameplay] ERROR: Invalid Reference on BuildingModifiers.BuildingType - "BUILDING_SUKIENNICE" does not exist in Buildings
[3577271.917] [Gameplay] ERROR: Invalid Reference on BuildingModifiers.BuildingType - "BUILDING_HUEY_TEOCALLI" does not exist in Buildings
[3577271.917] [Gameplay] ERROR: Invalid Reference on BuildingModifiers.BuildingType - "BUILDING_ANGKOR_WAT" does not exist in Buildings
[3577271.917] [Gameplay] ERROR: Invalid Reference on BuildingModifiers.BuildingType - "BUILDING_APADANA" does not exist in Buildings
[3577271.917] [Gameplay] ERROR: Invalid Reference on BuildingModifiers.BuildingType - "BUILDING_HALICARNASSUS_MAUSOLEUM" does not exist in Buildings
[3577271.917] [Gameplay] ERROR: Invalid Reference on BuildingModifiers.BuildingType - "BUILDING_JEBEL_BARKAL" does not exist in Buildings
[3577271.944] [Gameplay]: Failed Validation.
[3577274.816] [Configuration]: Validating Foreign Key Constraints...
[3577274.816] [Configuration]: Passed Validation.
[3577275.429] [FullTextSearch]: FTS - Creating Context
[3577295.435] [FullTextSearch]: FullTextSearch - Shutting down