Hello, I don't know anything about db files, but I think you should check folder FeralHeart/media/terrains on your old computer.
From there you can find data of all maps you left in map editor. For each map there should be 1 file named {map name}.map and 1 folder named {map name}.
You may want to copy those (it may be easiest to just copy whole folder) to the equivalent folder FeralHeart/media/terrains on your new computer and check if you can access them from the map editor.
Does this help?