Update: the problem is indeed with the door that leads to Port Royale store, and goes nowhere in Havana. When you try to enter, the reload code detects that there is no valid destination and bails out. Nobody will then talk to you, including your own officers. Going to any other valid location, e.g. the real store or Havana centre, restores all talking, even if you then return to the area with the store.
Additional update: I've commented out the lines in "PROGRAM\Locations\init\Cuba.c" which define the reload for "door_11" but lead nowhere. Then I found a few more dead-end reload definitions in some other location files, checked by going to the places in question that they cause the same error, and commented them out too. As of the 28th October update, you can go to the door in Havana without losing the ability to talk to people, and also a couple of places in Willemstad, Marigot, and the jungle on Turks Island.