I was using the newest gog version, and after 40 hours the crashes started. Every ten minutes or so. I was playing the same map for this whole time, and every island had something on it, 30 trading routes, 40000 citizens, and so on. A big map.
So I applied the 4GB patch to Anno4.exe, it was patched, but the crashes still came.
So I applied the patch also to Addon.exe and Benchmark.exe (because why not), and voila, it actually worked. No more crashes! I played for two hours straight, nothing! I have no idea how and why this works, but I'll take it.
If your version works fine, great, if it does not, this trick might be worth a shot!