when i marked all check boxes in settings,update fails.
- by user67966
"W:Failed to fetch cdrom://Ubuntu 12.04 LTS Precise Pangolin - Release i386 (20120423)/dists/precise/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 12.04 LTS Precise Pangolin - Release i386 (20120423)/dists/precise/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."
the above information is a crash info.It happens when i manually update ubuntu.I have marked all check-boxes in settings which was by default not marked. What is the main reason for this problem?