Walkthroughs for custom maps.

You need to cross the water without summoning a boat (you can't swim across, and the cursed land isn't suitable for sinking the boat; but there's a cell on lava at 107,131 above – you can use that to sink the boat). If you open the map in the editor and temporarily remove the cursed land, everything will become clear. The event prevents you from disembarking from the boat. I hope you still have a save before summoning the boat?