DebconfError

Here is a patch that solves the bug.

This bug was fixed in the package ubiquity - 1.7.7

---------------
ubiquity (1.7.7) hardy; urgency=low

  [ Mario Limonciello ]
  * Add ubiquity-frontend-mythbuntu.links to source exterior glade files.
  * Add temporary workaround to allow Mythbuntu installs on low res
    displays.
  * Fix case when no themes are removed.

  [ Colin Watson ]
  * Prevent apt-install from installing packages directly unless
    install_extras has been run (previously, it would do so once apt was
    configured, which produced some confusing error messages).
  * Call apt-setup finish-install script during cleanup, not while
    configuring apt; removing cdrom entries from sources.list at this point
    broke OEM installs and probably other things (LP: #188240).
  * Fetch http_proxy and no_proxy from gconf (if possible) immediately
    before configuring apt.
  * Update installed file list for apt-setup 1:0.31ubuntu3.
  * GTK frontend:
    - Add proxy configuration to the advanced dialog (LP: #131421).
  * Import DebconfError correctly in summary component (thanks, Jesus L.
    Alvaro; LP: #177442).
  * Build-depend on dctrl-tools rather than grep-dctrl.

  [ Evan Dandrea ]
  * Validate the boot device string that the user provides on the
    advanced page.
  * Change the boot device Entry to a ComboBox that displays suitable targets.
  * Updated the location of gnome-settings-daemon in ubiquity-dm.
  * Fix the installer window appearing briefly when starting automatic mode.
  * Explicitly call GDM/KDM at the end of ubiquity-dm as we now remove the rc
    files in casper for only-ubiquity and automatic-ubiquity.
  * Always show the advanced partitioner buttons, greying them out
    conditionally instead of hiding them.
  * Add the progress bar for automatic mode that was already present in
    gtk_ui to kde_ui.
  * Replace the resize slider with a custom widget in gtk_ui.
  * Automatic update of included source packages: apt-setup
    1:0.31ubuntu5, grub-installer 1.27ubuntu5, hw-detect 1.58ubuntu2,
    partman-partitioning 54ubuntu2.

  [ Agostino Russo ]
  * Added debug mode boot parameter

 -- Evan Dandrea <email address hidden> Wed, 13 Feb 2008 15:03:15 -0500