It looks like you have multiple shadow sources. I don't think Physical sun and sky should do that
Anyway, look for some more tweaking of that one - horizon height, blur etc. (stuff I've seen in Maya's help. take a look there...)
Also, the render quality is good enough for test renders but you're going to have to raise it later...
Benny
When in doubt, delete history and freeze transformations.
My latest snake game
(Requires DirectX9 SDK and Framework)