Postgresql 9.3 installation fails

It seems there was a bug in the 9.1 packages, but it should be fixed.

As indicated in the linked thread the issue could be resolved by running :

update-alternatives --remove postmaster.1.gz /usr/share/postgresql/9.1/man/man1/postmaster.1.gz

and then reinstalling postgresql-9.1:

apt-get install -f
apt-get install --reinstall postgresql-9.1