How did you input the terrain size? If you used the entry method the old classic editor used in the EE I Think that would cause your problem.
In the old editor you just raw input the "size" of the terrain in meters. In the EE you do it via "patches" So 1 patch = 64 meters.
So when you are adding terrain did you do it like this:
![[Linked Image]](http://i.imgur.com/QxF9P1B.png)
Or did you type 64 in the two left most fields? Because that terrain size would be enormous and the cause of your problem.
I find 6x6 patches to be a good workable size for most maps with plenty of buffer on the edges.
And just sort of a general rule, any tutorials or posts you see might have some type of erroneous information like that due to the classic/EE switch.