It's obvious what the problem is if you examine Wing's second screenshot carefully!
Wing, you seem to have configured the Texture editor
incorrectly. To start with, the path in the left hand dialog box says "game\Textures\Terrain\Detail\Default
" It should start with the "Materials", for example: "Materials/terrain/plains_ferns_wet
" since all the terrain textures are located in the "terrain" folder.
Secondly, the field where it says "Surface Type" is blank. That should show whatever name you gave to your selected texture.
I suggest you open the manual
, click the "Index" button at the top and then click the letter "H". After that, read the section called "How to paint a terrain
" because it contains instructions on how to add new textures to the terrain menu.