I have seen others also having this problem and I created a help ticket with GOG, but haven't heard back yet. I really love this game and want to be able to to finish it! Here is my situation:

When I was on the island the game did not crash at all. I did get occasional load errors where a bunch of text popped up about failure to load properly and when I went to the map the exploration data was gone. I did not ever continue play after a load error, I always closed the game and restarted and then loaded the same file and it always worked as long as I had freshly launched the game. (So I don't think the error is in my save/saves).

This was annoying, but something I was willing to deal with because I really love the game.

When I got to Mexico the first time the game crashed. I restarted the game and reloaded my last Hispaniola save and this time Mexico loaded up properly. I immediately saved, closed the game, and reloaded, just to make sure all was OK. The save would not load without errors. I tried about 5 times, all with restarts. Today I read that some people need to reduce graphic quality, I set everything to minimum and 1024x768 resolution. I took the boat to Mexico, looked at the map, talked to the village, and then saved and quit. I reloaded and all was well. I set resolution to max again, saved, and restarted and reloaded, all good. I bumped graphics up from lowest to second to lowest and saved and restarted and loaded and it worked. I decided I was happy with that result and continued playing. Got to my first battle, and crash.

Both battle crashes and loading errors are reported all over the internet, yet the devs don't seem to be doing anything about it and people are just left to guess at a solution. I tried to report the problem on their webpage, but the community section is disabled for this game. I'm not even sure changing my graphics setting really made a difference, it could have been a coincidence. Furthermore, as I exceed the minimum system reqs and I don't run any extraneous software/drivers there is no excuse for the game crashing due to my system specs. Some of the people reporting the loading issue (which is generally believed to be memory related) are reporting that they have 8 gigs or more ram and the game only requires 2 gigs. I can run way higher req games, even quite a few that I don't quite meet the requirements for and they are at the very least stable. I was enjoying this game so much I almost bought the sequel yesterday. Glad I held off as I won't support a dev who is not interested in supporting their product.

Any advice or ideas would be greatly appreciated. Or if anyone knows a way to get in touch with the devs directly so that they can maybe look into the problem that would also be great. Thanks.