I am also having the exact same problem.
I reach the NAPA outpost after Novy Sabor, the game autosaves then loads, but hangs on the loading screen.
When I quit the game and re-load the autosave it corrupts, so I have to manually delete the latest autosave and revert back to an earlier save. When I try again to talk to the two NAPA guys and say the "Bitter chill" password, the game again autosaves then goes to a loading screen where it hangs indefinitely.
There seems to be no way around this and it has basically broken the game- I cannot go any futher in the campaign.
So I have effectively been robbed by Bohemia as I have paid for a game they simply haven't delivered. Has anyone a solution?