Here's the rendered image. The problem is with the shadows on the green object's right side. It's like a weird wave shaped shadow. And I get this result in all my renders where I use subsurf and smooth shading. I don't know if it has anything to do with them. Help if you can, please. Many thanks
I've tried a few changes based on the two links, but it's still the same. So gandalf3, it's not the same question, the problem is different, as it seems.