See postgre tables from PHP code

Hi everybody:

I'm relatively new to PHP programming and I was recommended to use
PostgreSQL as the site's database. However I haven't able to see my DB's
tables from PHP. Here is my (very simple, I think) code:

$pg = pg_connect("host=localhost port =5432 dbaname = ATM user=postgres
password = mypassword");
pg_query($pg,"select nick,contrasenna,nombre,apellidos from usuarios");

Beside, I opened my PostgreSQL interface, called pgAdmin and run the same
query inside the ATM database and the error was the same: "relation
'usuarios' was not found". It's like something else was needed to access the
DB tables.