zainstaluj stosowną wtyczkę a nastepnie odblokuj w PHP.INI
Detailed installation guides - PostgreSQL wiki
You need to install the pgsql module for php. In debian/ubuntu is something like this:
Bash:sudo apt-get install php5-pgsql
Or if the package is installed, you need to enable de module in php.ini
INI:extension=php_pgsql.dll (windows) extension=php_pgsql.so (linux)