MechaProcess 62 error

I have two of these printers that keep picking up multiple sheets of paper at a time and giving mechaprocess 62 errors. The manual only says that it is an internal error and to contact sony to clear it. After clearing the error it repeats the next time it is used. Sony reports that the only option is to send it in for repair. These units have already been sent in once for this and no problem was found. Does anyone have any information on the cause of or solution for this error?