Im Getting this error as well.
I deleted the following from Blackmarket_1.2.1.zip\prototypes\extensions\goldmining.lua and got the game to load.
From what the note says and what I know of Lua, its changing something within goldmining, I think one of the stone processing recipes and faulting out. Getting rid of the change gets rid of the problem.
"
-- slighty update gold processing technologies to not waste stone
table.each(data.raw.recipe["gold-processing"].results, function(result)
if result.name == "stone" then
result.amount = 3
end
end)
"
Loaded a previous factory which did not have the mod, and it loaded just fine. Technology's are present. Buy & Sale of items works fine. Havent tested Fluids or Power but I think your Gold. (Pun Intended, #NotSorry)