Comment 4 for bug 1165172

The problem is that the following events happens:
= = = = =
Selecting previously unselected package libpython2.7-minimal:amd64.
Unpacking libpython2.7-minimal:amd64 (from .../libpython2.7-minimal_2.7.4~rc1-4ubuntu1_amd64.deb) ...
Replacing files in old package python2.7-minimal ...
Preparing to replace python2.7-minimal 2.7.3-5ubuntu4 (using .../python2.7-minimal_2.7.4~rc1-4ubuntu1_amd64.deb) ...
Unpacking replacement python2.7-minimal ...
Processing triggers for gconf2 ...
dpkg: error processing gconf2 (--unpack):
 gconf2
Preparing to replace gconf2-common 3.2.5-0ubuntu4 (using .../gconf2-common_3.2.6-0ubuntu1_all.deb) ...
Unpacking replacement gconf2-common ...
Preparing to replace libgconf2-4:amd64 3.2.5-0ubuntu4 (using .../libgconf2-4_3.2.6-0ubuntu1_amd64.deb) ...
Unpacking replacement libgconf2-4:amd64 ...
Preparing to replace gconf2 3.2.5-0ubuntu4 (using .../gconf2_3.2.6-0ubuntu1_amd64.deb) ...
Unpacking replacement gconf2 ...
Setting up gconf2-common (3.2.6-0ubuntu1) ...
Selecting previously unselected package libpython2.7-stdlib:amd64.
Unpacking libpython2.7-stdlib:amd64 (from .../libpython2.7-stdlib_2.7.4~rc1-4ubuntu1_amd64.deb) ...
= = = = =

So in this case, the trigger for gconf2 will use modules from the new libpython2.7-minimal which requires libpython2.7-stdlib while libpython2.7-stdlib is not yet unpacked and configured. This is not specific to gconf2 and should be reproducible with other pacakges.