I have 3 Nikon F100 and all my lens are AF although I don't have yours.
That's an all plastic lens designed to be a kit lens, so AF will not be fast. That said, it should still focus accurately and within reasonable amount of time.
All AF lens will hunt (meaning try to focus repeatedly) when there is insufficient light or your camera is confused about what it should be focusing. It will also hunt when it can't focus because objects on the focus point are to close.
If you try to focus under good lighting and place a single, non-moving object with nothing confusing right next to it, and give it time, does it still hunt and fail to focus?
What focus mode are you using? I use single point focus almost all the time and have a focus point locked in the center.
One more.... which setting do you have the focus limit switch set to? Set it to FULL and try it again. When set to LIMIT, it will not focus for distance objects.