Comment 14 for bug 751725

I get the same crash with the trace below,
(Fresh quantal 20121012 amd64 install -> Re-install quantal desktop 20121012 i386 keeping the personal files and then use software center to install any application e.g. virt manager)

Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/defer/__init__.py", line 487, in _inline_callbacks
    result.traceback)
  File "/usr/share/software-center/softwarecenter/backend/installbackend_impl/aptd.py", line 957, in _medium_required
    yield transaction.cancel(defer=True)
aptdaemon.errors.AptDaemonError: org.debian.apt: Could not cancel transaction
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/defer/__init__.py", line 487, in _inline_callbacks
    result.traceback)
  File "/usr/share/software-center/softwarecenter/backend/installbackend_impl/aptd.py", line 957, in _medium_required
    yield transaction.cancel(defer=True)
aptdaemon.errors.AptDaemonError: org.debian.apt: Could not cancel transaction