Get the following error:

Failed to fetch cdrom:[Ubuntu-Server 8.04 _Hardy Heron_ - Beta amd64 (20080318.1)]/dists/hardy/main/binary-amd64/Packages.gz Please use apt-cdrom to make this CD-ROM recognized by APT. apt-get update cannot be used to add new CD-ROMs
Failed to fetch cdrom:[Ubuntu-Server 8.04 _Hardy Heron_ - Beta amd64 (20080318.1)]/dists/hardy/restricted/binary-amd64/Packages.gz Please use apt-cdrom to make this CD-ROM recognized by APT. apt-get update cannot be used to add new CD-ROMs