Some Problems with the terrain

Hello,
I have some problems with my terrain.
If I don't use Caelum then I don't see my terrain.(I do have ambient and normal light setup)
However if I do use Caelum then the terrain is a weird light blue color.
I use the terrain from the samples.

Does anyone knows what is causing this problem ?

Thanks in advance !

anyone?

try this:

mSceneMgr->setOption("LoadNow", NULL);