LoadFile "C:/Program Files/PostgreSQL/9.1/bin/libpq.dll"
Then edit the php.ini file (in folder : C:\xampp\php). Enable this lines:
extension=php_pdo_pgsql.dll
extension=php_pgsql.dll
Environment:
- Windows 7
- XAMPP
- XAMPP Control panel v3.2.1
- PostgreSQL 9.1
Reference: