This tool is primarily designed for our newer Kickstarted titles, since there is a window of time between the release of the early backer PDFs and when the print version will be sent to the printer. This gives us a chance to fix issues before the physical books go live. But feel free to report errors from older titles... but there's no need to report the misspelling of 'alter' in the Sunken City adventures... those I know only too well. :)
Please include the page and paragraph number of the error(s) you discover, as that is enormously helpful in quickly fixing the problem.