Update Manager and Synaptic have both been having similar problems on my Jaunty installation recently.

For example, when Update Manager tried to install
Important security updates

libneon27
An HTTP and WebDAV client library

libneon27-gnutls
ditto (GnuTLS enabled)
It failed with the following message:
dpkg: failed in buffer_read(fd): copy info file '/var/lib/dpkg/available': Input/output error
E: Sub-process /usr/bin/dpkg returned and error code (2)
A package failed to install. Trying to recover:
dpkg: failed in buffer_read(fd): copy info file '/var/lib/dpkg/available': Input/output error
I also encountered similar errors when I tried to use Synaptic to install Acidrip and k3b, i.e. dpkg had problems accessing /var/lib/dpkg/available

Researching the problem took me to a locked thread on this forum and I tried the advice I found there:
Code:
sudo dpkg --clear-avail
After that, I tried Update Manager again but it got very upset, reporting:
Could not initialise the package information

An unresolvable problem occurred while initialising the package information.

Please report this bug for the 'update-manager' package and try to include the following error message:

'E:Could not open file /var/lib/apt/lists/gb.archive.ubuntu.com_ubuntu_dists_jaunty_multiver se_i18n_Translation-en%5fGB - open (2 No such file or directory), E:Could not open file /var/lib/apt/lists/gb.archive.ubuntu.com_ubuntu_dists_jaunty_universe _i18n_Translation-en%5fGB - open (2 No such file or directory), E:Could not open file /var/lib/apt/lists/gb.archive.ubuntu.com_ubuntu_dists_jaunty_restrict ed_i18n_Translation-en%5fGB - open (2 No such file or directory), E:Could not open file /var/lib/apt/lists/gb.archive.ubuntu.com_ubuntu_dists_jaunty_main_i18 n_Translation-en%5fGB - open (2 No such file or directory)'
Undeterred, I tried again and this time Update Manager seemed perfectly happy. I told it to "Check" and all seemed well again. Furthermore, Synaptic has now successfully installed acidrip and k3b, the packages that it failed with previously.

Am I in the clear now?

Do I still need to report the "bug" that update manager got so upset about and, if so, how/where?