can't connect to a postgreSQL database from PHP

HelpHi everybody!

I've got a problem using PHP to connect to a postgre database, it seems that
the function for postgre are not recognized or something like that because a
I get the following error in the web navigator:
"Fatal Error: Calling to undefined function pg_connect() ...)"

I configured php with: ./configure --with-apache=/usr/local/apache_1.3.26
                                                 --with-pgsql=shared
                                                 --enable-track-vars
                                                --with-xml
after that I reconfigured Apache to take into account php:

                               ./configure --prefix=/usr/local/apache_1.3.26
                                                --activate-module=src/module
s/php4/libphp4.a


Any idea to solve it?

Thank you all.