My wife's Ixus  could not be used because the film compartment would not close; the top would not click shut when pressed down.  I bought another on Ebay as I think this is a brilliant little camera.  When the new one arrived I decided to take the old one apart.  On losening the screw nearest the film compatrtment by half a turn I discovered that the film compartment now closes perfectly.  This may not answer your query directly, but having been quoted £70 by Canon to look at the Ixus, I had to share this simple solution.
                 Paul O'Brien
                
 March 2007