Have you deleted any objects? If your map contains objects from the object group you deleted, then it can cause issues.
Try deleting any particles in your map and re-exporting and see if it works. Or just try to re-export without changing anything.
Note: If your game freezes, do not click the screen.
Might not be the best solution but, have you tried having someone else export the map for you? An scapeboat if your problem cant be solved.
Other than that, could you provide screenshots? I am no expert on this, but perhaps it could help us shed light onto the problem
If you have particles in the map and export it, always go into your particles folder and delete anything ending in _0 or _1 (or any other number). Those are a lot of the reason maps crash the game.