Try deleting all of the files in the '..\Divine Divinity\Run\Dynamic' folder, then start Divinity and re-load the game.
This folder is used as a cache for the game. Files are created / copied there from the save game folder when you load, and written / copied from that folder when you save a game. The files will be re-created as required the next time you start Divinity. If there was a corrupt file in that folder, deleting the files should fix the problem.
If that doesn't help, The fog-of-war for the Dark Forest is stored in the shroud.x2 file. I think you should be able to safely replace this with a file from a recent working save, but make a copy of your latest save game folder first, just in case. The 6 inv.* files keep track of your inventory and all NPC trade inventories, as well as the contents of all chests. Check you home base and make sure all your stored loot is still there. The data.000 file keeps track of your location and the location / status of all monsters and NPCs, so fortunately that appears to be fine.
