Comment 20 for bug 1015567

To add more details to such problem, I tried to revert the source as:

   sudo sed -i.dist 's,quantal,precise,' /etc/apt/sources.list

and then did the update and dist-upgrade. The same error persist:

dpkg: error: parsing file '/var/lib/dpkg/status' near line 75249 package 'libstdc++5:i386':
 mixed non-coinstallable and coinstallable package instances present
E: Sub-process /usr/bin/dpkg returned an error code (2)
root@bkgovsrv1:~#