Canon POWERSHOT A720 IS User Manual page 21

List of Messages
1161
An error was detected while the lens was in motion, and the power
has been automatically turned off. This error can occur if you hold
the lens while it is in motion or you operate it in a location with
excessive dust or sand in the air. Try turning the power back on, and
resume shooting or playback, tf this message continues to display,
contact your Canon Customer Support Help Desk as there may be a
problem with the tens.
(xx: number) Camera detected error. Turn the power off and then
back on, then shoot or play back. A problem exists if the error code
reappears. Note the number and contact your Canon Customer
Support Help Desk. tf an error code displays directly after taking a
picture, the shot may not have been recorded. Check image in
playback mode.