PRoblem with lens AF lamp?

I use a Nikon D3100 with a 18-55 AF VR lens… Suddenly I find a slight shadow appearing in the AF lamp's light when I project the light on a nearby wall. Please do tell me what exactly is the problem and what is the solution.

Means nothing… Is the lens in the way? Your finger? What kind of "shadow"?

Dirt inside the lamp? That's normal. If you are worried, you can have it cleaned or replaced at an authorized Nikon service center.

Probably means you have a lens hood on, which is good. Provided the lens can find focus using the AF assist light in low light what's the problem?