Comment 3 for bug 539347

debconf (developer): <-- METAGET apt-setup/progress/cdrom description
debconf (developer): --> 1 Scanning the CD-ROM...
Mar 15 16:50:13 debconf (filter): --> 0 OK
The ERROR occurs around this time. I provided a snapshot of the time window, below from "debug" file:

Mar 15 16:50:31 debconf (filter): <-- INPUT critical apt-setup/cdrom/failed <<<SEE HERE <<<
debconf (developer): <-- METAGET apt-setup/cdrom/failed Type
debconf (developer): --> 1 error
Mar 15 16:50:31 debconf (filter): error widget found for apt-setup/cdrom/failed
debconf (developer): <-- METAGET apt-setup/cdrom/failed description
debconf (developer): --> 1 apt configuration problem
debconf (developer): <-- METAGET apt-setup/cdrom/failed extended_description
debconf (developer): --> 1 An attempt to configure apt to install additional packages from the CD failed.
/usr/lib/ubiquity/ubiquity/frontend/gtk_ui.py:1295: GtkWarning: Ignoring the separator setting
  dialog.set_has_separator(False)
Mar 15 16:51:30 debconf (filter): --> 0 question will be asked
Mar 15 16:51:30 debconf (filter): <-- GO
debconf (developer): <-- GO
debconf (developer): --> 0 ok