Well, I was really upset when my beloved Canon PS SX10IS gave me a 'Lens Error, Restart Camera' message. Then it shut off, and I couldn't even access the 'review' feature to see the photos I had just taken! I replaced the batteries, but that didn't fix it. In looking at the lens carefully as it was trying to open, I noticed some white caulky-like material peeking out from under the outer lens ring. In fiddling with it, the outer ring came off. I could see that the caulk was like a glue, holding that plastic ring in place. The camera worked fine w/o the ring, opening, focusing, and shooting. The outer plastic ring was only acting as a protection for the camera's 'insides' when it was fully extended in zoom position. Knowing how much the fix is, I decided to try to fix it myself. I removed the caulk that seemed to be in excess, left what I could and snapped the ring back in place, paying attention to fit the appropriate parts together. It's now firmly in place and the camera works again perfectly. The lens extenstion/zoom was catching on the loose caulk.
I tend to carry the camera by the lens. Am sure that this is what caused it to loosen from the caulk.
Good Luck!