Falling Through The Map HELP

[Blitz2530]

So Im making a rather large map (30000 x 500) and when I get near the ends of it, and within a rather large margin, I fall through the land. I dont know why this is happening, but the camera in editor mode goes right through the ground as well.
Help? Please?

[Redlinelies]

Just keep in mind, that both the heightmap image and the size of the map inside the map maker should stay identical on both sides, otherwise you will get problems like these.

I'm not sure where to limit goes for a map size either, but it should be rather big.

Also, make sure that you set a boundary limit more than 10, it will ensure so you wont be able to get to edges of map.