First page via Google when asking about the E18 error from my less than six month old Canon IXUS 700. Courtesy of www.ixus-world.de:
The E18 error message is the worst that can happen to an owner of the Canon IXUS. By manky mechanics the camera cannot drive their lens out any longer and displays the error “E18” in the lcd display. If the warranty of the camera has ran out it’s not worthwhile to repair it by Canon in most cases. With a little luck you can repair the damage by yourself..
Then what a coincidence — drive over to the Canon service centre at lunch time to drop my camera off and there’s one guy waiting at the counter ahead of me. Surprise, surprise, he’s dropping off an IXUS750 with exactly the same problem. Of course the service desk staff claim that they’ve never seen it before on any camera….