Model appears black or not atall

I exported a model with oFusion and viewed it with CeguiMesh viewer. everything was all right, material worked, animations worked!

but when I tried to it for real with NxOgre it appeared black and sometimes it didn't show at all :/

Character *tester = mScene->createCharacter(name, Vector3( x, y, z ), CharParams);
tester->attachMesh("cone1.mesh");

anyone know what is wrong?

Do you have lights in your scene (and are the objects in the light range)?