lighting and normals

hi, I am having trouble with lighting…

I have my light as a directional one pointing at 0,-1,0 (directly down) and normals defined as 0,1,0 (directly up), but when i execute the program things in front of the viewer (i can turn the camera) are lit, but things behind i.e. when i turn the camera are not… can anyone help correct this

to give a little more info the light IS being transformed when I move or turn or whatever…