[Forager]

GF_Mastiff, are these lines in your MODS\Mapmods\all file?
The_Slot_01-44 Slot/load_0144.ini
The_Slot_07-43 Slot/load_0743.ini
The_Slot_08-42 Slot/load_0842.ini
The_Slot_10-42 Slot/load_1042.ini
The_Slot_10-43 Slot/load_1043.ini
The_Slot_12-42 Slot/load_1242.ini

Do the Slot maps show in the Full Mission Builder?

You might try to reinstall the Slot map.