The pilot stated that during his first ILS approach, the localizer needle fluctuated to the left. He made corrective turns to the left. When he broke out of the clouds at the decision height (DH), he observed the runway to the right and made a missed approach. At that time, he assumed that he made an error due to a cockpit distraction when he turned on his landing light. He reported the same type of problem during his second ILS approach, except the fluctuations were larger. At the DH, both of his ILS localizer needles showed that he was right of course. He saw a row of lights to his left that he thought was the runway. After he turned left and descended, he realized they were street lights. During his climb for another approach, the right wing struck a tree. He encountered the same ILS problem on a third approach, but landed safely. A check of the ILS transmitters and both receivers revealed no malfunction or failure. The plane had an autopilot front/back switch, which was reportedly set on "FRONT".