It appears something happened at the end of the Davey Jones quest. I thought I finished it, but there are hangovers. I fought Davey Jones twice at sea and his crew twice on land. When it was over I saved and exited. The next day I had small problems at Cayman, but got away ok. Went to Bonaire and now, whether coming or going, on the pier I get a dialogue asking whether or not to go after a Spaniard and a daughter. If I agree I get stuck on a deck looking at a girl but unable to move . So I decline now and move on. But I can't get back to Cayman! No matter if I use the world map or 3d sailing it ctd's when I get close. If an error message from macroshaft shows up, the offending item is "sea_ai.dll" the last three attempts, but I have also gotten "geometry.dll" and "stackhack" errors. I don't want to do a complete reinstall. Is there hope?
But the merchant didn't show. Went looking for him, but he wasn't in the tavern or store. Went out to his ship and found him in his cabin. He started talking about a fight and my ship is at Palm Beach. :? I decided he had been drinking too much seawater and put him out of his misery. 
Things went well after that. 
Got past that and went to get in my ship, and it ctd'ed. The "stackhack" thing....... 
Sheesh.