W: Failed to fetch cdrom://Ubuntu 15.10 _Wily Werewolf_ - Release amd64 (20151021)/dists/wily/main/binary-amd64/Packages  Please use apt-cdrom to make this CD-ROM recognized by APT. apt-get update cannot be used to add new CD-ROMs

W: Failed to fetch cdrom://Ubuntu 15.10 _Wily Werewolf_ - Release amd64 (20151021)/dists/wily/restricted/binary-amd64/Packages  Please use apt-cdrom to make this CD-ROM recognized by APT. apt-get update cannot be used to add new CD-ROMs

W: Failed to fetch cdrom://Ubuntu 15.10 _Wily Werewolf_ - Release amd64 (20151021)/dists/wily/main/binary-i386/Packages  Please use apt-cdrom to make this CD-ROM recognized by APT. apt-get update cannot be used to add new CD-ROMs

W: Failed to fetch cdrom://Ubuntu 15.10 _Wily Werewolf_ - Release amd64 (20151021)/dists/wily/restricted/binary-i386/Packages  Please use apt-cdrom to make this CD-ROM recognized by APT. apt-get update cannot be used to add new CD-ROMs

E: Some index files failed to download. They have been ignored, or old ones used instead.