I'm running into the following error when I'm installing any package on 12.04.

Reading package lists... Done

Building dependency tree       

Reading state information... Done

You might want to run 'apt-get -f install' to correct these.

The following packages have unmet dependencies:

 postgresql-client-9.1 : Breaks: postgresql-9.1 (< 9.1.7-0ubuntu12.04) but 9.1.6-1~precise2 is installed

E: Unmet dependencies. Try using -f.

Tried following commands,

sudo apt-get autoremove

sudo apt-get autorclean

sudo apt-get install -f

sudo apt-get purge postgresql

sudo apt-get purge postgresql-client-9.1

sudo apt-get autoremove --purge postgresql-client-9.1

sudo apt-get autoremove --purge postgresql

sudo apt-get remove --dry-run postgresql

sudo apt-get update

etc. But none of this could save me. Any idea?