my postgres connection failing

[Nicodemo Alvaro]

I am getting this message from my setup:

Fatal error: Call to undefined function pg_connect() in
/var/www/gnuherds-app/gnuherds-app/Layer-5__DB_operation/PostgreSQL.php
on line 35

--EOR--
I am using debian etch. I installed the libapache2-mod-auth-pgsql
package and enabled it.