Ah, yes. The particles could be the culprit. Go into your C: >>> Feralheart >> media > particles and delete any ending in _0, _1, and so on. Sometimes particles double when they are exorted, causing the map to crash. Particles can also get themselves into the my_objects folder, so it wouldn't hurt to check there. ^^
Also, make sure your map is 513 x 513! That's very important.
If you don't find particles in those folders, search them in your PC.
Lastly, does your map have many objects? That can cause the map to crash.