Help me photographically

Since last 4-6 weeks I am seriously trying my hands on night photography. My attempts also increased manyfold after a tripod was added to my kit, thanks to Amit, my bro-in-law. But as my night photo-stock grew, so does my worries.

Initially there were many green spots in my shots, as evident from following photos:

I thought that the reason of these light streaks was dust/scratch on the lens or sensor. But the spots were at different positions in all the photos. So I am skeptical about above reasons.

If the above photos were cause of worries, following photos were hard to believe. Can you spot any serious error in those?

How can a camera produce mirror image internally? Its beyond my imagination.

I am using Nikon D60 with Nikkor 18-55 lens and a UV filter.

Please help me if you have faced some similar problem.