UN-believeable. I JUST had this SAME problem happen to me TONIGHT! How freakin' frustrating that this just now happened! I am floored at the customer service that S400 is saying. That is completely unbelievable that a faulty piece of theirs would not be on warranty.
If anyone has any new information on this, PLEASE let me know at laffingleigh@hotmail.com
I purchased a Canon S400 camera for roughly $500 a little over a year ago. The camera recently stopped working for no apparent reason due to an E18 error (lens focus mechanism). The camera was not mis-handled. The warranty is 1 year. The service center indicated it would cost me $150 to inspect and repair this problem. Alternatively, they offered me a refurbished replacement at an even higher cost! Apparently, the E18 error related to the focus mechanism is common and part of a fault design. Needless to say, I communicated with Canon service reps that their repair/replacement options were not acceptable and asked for an exception to replace or repair the camera for free. I also asked Canon to describe their customer dispute resolution process. They could not.
After speaking with their customer service organization all the way up to senior management and corresponding with their tech service via email, it has become evident that Canon really doesn't stand behind their faulty products and is not customer service oriented. The entire experience was a long process of "passing the buck?. I am extremely disappointed and will never buy a Canon product again. I recommend you do not buy a Canon either.
Has anyone else had this problem?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic