unable to upgrade debian etch from 8.6 to 9: serious bugs of xinetd

[maumar]

i get this error during upgradeing to plesk 9 by panel:

Reading package lists...
Building dependency tree...
Suggested packages:
  sqlite3-doc
The following packages will be REMOVED:
  psa-courier-imap-add* psa-hotfix3* psa-hotfix4* psa-hotfix5*
The following NEW packages will be installed:
  libspf2-2 plesk-base psa-hotfix3-9.0.0 psa-mail-driver-common
  psa-mail-qc-driver sqlite3 sw-cp-server sw-engine sw-libboost1.34-filesystem
  sw-libboost1.34-program-options sw-libboost1.34-regex sw-sso xinetd
The following packages will be upgraded:
  libpam-plesk log4cpp-plesk plesk-billing plesk-skins psa psa-api psa-api-rpc
  psa-awstats-configurator psa-backup-manager psa-ftputil
  psa-locale-base-en-us psa-manual-custom-skin-guide psa-migration-manager
  psa-php5-configurator psa-proftpd psa-proftpd-inetd psa-pylibplesk psa-qmail
  psa-updates psa-watchdog
20 upgraded, 13 newly installed, 4 to remove and 39 not upgraded.
Need to get 2648kB/67.1MB of archives.
After unpacking 3030kB disk space will be freed.
WARNING: The following packages cannot be authenticated!
  sw-cp-server sw-engine sqlite3 sw-sso sw-libboost1.34-filesystem
  psa-locale-base-en-us psa-api plesk-base psa-php5-configurator plesk-skins
  xinetd psa-qmail libspf2-2 psa-mail-driver-common psa-mail-qc-driver psa
  plesk-billing psa-watchdog psa-backup-manager psa-migration-manager
  psa-pylibplesk libpam-plesk psa-api-rpc psa-updates
  psa-manual-custom-skin-guide log4cpp-plesk sw-libboost1.34-program-options
  sw-libboost1.34-regex psa-ftputil psa-hotfix3-9.0.0 psa-proftpd
  psa-proftpd-inetd psa-awstats-configurator
Authentication warning overridden.
Get:1 http://autoinstall.plesk.com etch/all psa-migration-manager 9.0.0-debian4.0.build90081208.07 [2648kB]
serious bugs of xinetd ( -> 1:2.3.14-1) <done>
 #427892 - circumvents invoke-rc.d (and thus policy-rc.d) in postinst (Fixed: xinetd/1:2.3.14-1.1)
Summary:
 xinetd(1 bug)

****************************************************************************
****** Exit with an error by force in order to stop the installation. ******
****************************************************************************
E: Sub-process if dpkg -s apt-listbugs | grep -q '^Status: .* ok installed'; then /usr/sbin/apt-listbugs apt || ( test $? -ne 10 || exit 10; echo 'Warning: apt-listbugs exited abno
rmally, hit enter key to continue.' 1>&2 ; read a < /dev/tty ); fi returned an error code (10)
E: Failure running script if dpkg -s apt-listbugs | grep -q '^Status: .* ok installed'; then /usr/sbin/apt-listbugs apt || ( test $? -ne 10 || exit 10; echo 'Warning: apt-listbugs
exited abnormally, hit enter key to continue.' 1>&2 ; read a < /dev/tty ); fi
Fetched 2648kB in 2s (1225kB/s)
-- Check for new version of PSA_9.0.0/plesk-9.0.0-deb4.0-i386.inf3
Filefetcher: get file (~empty)/PSA_9.0.0/plesk-9.0.0-deb4.0-i386.inf3
Execute command apt-get update
Get:1 http://debian.fastweb.it etch Release.gpg [386B]
Hit http://debian.fastweb.it etch Release
Ign http://debian.fastweb.it etch/main Packages/DiffIndex
Ign http://debian.fastweb.it etch/contrib Packages/DiffIndex
Ign http://debian.fastweb.it etch/non-free Packages/DiffIndex
Ign http://debian.fastweb.it etch/main Sources/DiffIndex
Hit http://debian.fastweb.it etch/main Packages
Hit http://debian.fastweb.it etch/contrib Packages
Hit http://debian.fastweb.it etch/non-free Packages
Hit http://debian.fastweb.it etch/main Sources
Get:2 http://security.debian.org etch/updates Release.gpg [189B]
Hit http://security.debian.org etch/updates Release
Ign http://security.debian.org etch/updates/main Packages/DiffIndex
Hit http://security.debian.org etch/updates/main Packages
Fetched 2B in 0s (13B/s)
Reading package lists...
ERROR: An error occurred on attempt to install packages.
Attention! Your software might be inoperable.
Please, contact product technical support.

upgrade is stopped and system is unchanged (luckily)