What do you suggest I do?

Basically, I deleted everything related to mercury, stone, wood, and gold from that folder, including what drops from the mill, and now it works. Check your resource models; see what you replaced, for example, with mercury.

P.S. The same thing is happening with mercury in your NVS_ImportObjects.pak file. It seems that anything that drops from the mill in that mission, if it's not a standard resource model, makes everything black. I'm not sure, but if gems or other resources with new models were dropped, it would probably be the same.