Hi. I was having this problem before I updated to "update-notifier - 0.119ubuntu7", but it seems like the problem is still there for me even after the update. I just installed yesterday Ubuntu Server 12.04 beta 2 64 bit + kubuntu-desktop on top of it. Got the same message window "packages requested additional data downloads after package installation, but the data could not be downloaded" for ttf-mscorefonts-installer and also flashplugin-installer when trying to install kubuntu-restricted-extras from the Muon Package Manager.
When I press "Run this action now" in the message window, a bash shell opens up with the following lines:

Warning: Could not find 'gksudo', starting '/bin/bash' instead.  Please check your profile settings.

/usr/lib/update-notifier/package-data-downloader: line 3: Process new requests to download per-package data: command not found
/usr/lib/update-notifier/package-data-downloader: line 19: import: command not found
/usr/lib/update-notifier/package-data-downloader: line 20: import: command not found
/usr/lib/update-notifier/package-data-downloader: line 21: import: command not found
/usr/lib/update-notifier/package-data-downloader: line 22: import: command not found
/usr/lib/update-notifier/package-data-downloader: line 23: import: command not found
/usr/lib/update-notifier/package-data-downloader: line 24: import: command not found
/usr/lib/update-notifier/package-data-downloader: line 25: import: command not found
/usr/lib/update-notifier/package-data-downloader: line 26: import: command not found
/usr/lib/update-notifier/package-data-downloader: line 27: import: command not found
/usr/lib/update-notifier/package-data-downloader: line 28: import: command not found
/usr/lib/update-notifier/package-data-downloader: line 29: import: command not found
from: can't read /var/mail/datetime
/usr/lib/update-notifier/package-data-downloader: line 32: DATADIR: command not found
/usr/lib/update-notifier/package-data-downloader: line 33: STAMPDIR: command not found
/usr/lib/update-notifier/package-data-downloader: line 34: NOTIFIER_SOURCE_FILE: command not found
/usr/lib/update-notifier/package-data-downloader: line 35: NOTIFIER_FILE: command not found
/usr/lib/update-notifier/package-data-downloader: line 36: NOTIFIER_PERMANENT_SOURCE_FILE: command not found
/usr/lib/update-notifier/package-data-downloader: line 37: NOTIFIER_PERMANENT_FILE: command not found
/usr/lib/update-notifier/package-data-downloader: line 39: failures: command not found
/usr/lib/update-notifier/package-data-downloader: line 40: permanent_failures: command not found
/usr/lib/update-notifier/package-data-downloader: line 42: syntax error near unexpected token `('
/usr/lib/update-notifier/package-data-downloader: line 42: `def create_or_update_stampfile(file):'

The "Run this action now" button is grayed out after that, and the message window stays there until I press "Close" in it. Ttf and Flash are not installed after that. Reinstall from Muon repeates this message.

Here are some lines from /var/log/apt/term.log related to ttf and flash plugin:

Processing triggers for man-db ...
Processing triggers for libglib2.0-0 ...
Processing triggers for fontconfig ...
Processing triggers for update-notifier-common ...
ttf-mscorefonts-installer: downloading http://downloads.sourceforge.net/corefonts/andale32.exe
Traceback (most recent call last):
  File "/usr/lib/update-notifier/package-data-downloader", line 234, in process_download_requests
    dest_file = urllib.urlretrieve(files[i])[0]
  File "/usr/lib/python2.7/urllib.py", line 93, in urlretrieve
    return _urlopener.retrieve(url, filename, reporthook, data)
  File "/usr/lib/python2.7/urllib.py", line 239, in retrieve
    fp = self.open(url, data)
  File "/usr/lib/python2.7/urllib.py", line 197, in open
    name = 'open_' + urltype
TypeError: cannot concatenate 'str' and 'NoneType' objects
flashplugin-installer: downloading http://archive.canonical.com/pool/partner/a/adobe-flashplugin/adobe-flashplugin_11.2.202.228.orig.tar.gz
Traceback (most recent call last):
  File "/usr/lib/update-notifier/package-data-downloader", line 234, in process_download_requests
    dest_file = urllib.urlretrieve(files[i])[0]
  File "/usr/lib/python2.7/urllib.py", line 93, in urlretrieve
    return _urlopener.retrieve(url, filename, reporthook, data)
  File "/usr/lib/python2.7/urllib.py", line 239, in retrieve
    fp = self.open(url, data)
  File "/usr/lib/python2.7/urllib.py", line 197, in open
    name = 'open_' + urltype
TypeError: cannot concatenate 'str' and 'NoneType' objects

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I use a direct access to the Internet, no proxies.
So, is it still Bug #979477, or similar Bug #977178 , or maybe something new? Any ideas on how I should proceed with the installation?