I have one of these and it has survived being dropped so hard the lens cover broke off. Researching the issue you raise unearthed the following:
"taking the battery out for a couple of minutes and trying to open the lens again, or
banging the living hell out of the thing on a hard surface to see if that will knock some sense into it.
Seriously, the experts at the various camera sites that shall remain unlinked are unanimous in their advice that the best thing to do is to smack the side of the camera repeatedly on a hard surface and hope the lens error goes away and the camera lens opens back up."
Frankly you have nothing to lose as Canon will try to charge you more for repairing it than the camera costs secondhand.