Bug#817259: sorry, problem is due to corrupted DVD

["G. Cabrele" <gcab_dzan@libero.it>]

Thanks to the help received from "Debian Forum" I could determine that 
the the 2nd and 3rd DVD had a wrong md5sum, although they passed the 
integrity check.
Sorry for the fake alert, the installer is actually ok, thanks for your 
work.