connection error

Hi, i had installed postgress 7.3 in a database server, and php is running in an apache web server.
There are 6 databases. I can access to one of then from a php pages, and the system work fine.
The problem is when I want to access from a php page to another database. The conection is failed.
I had created this database using next comand:

createdb expedientes

And from phppgadmin (2.4.2) I had add privileges to a user. And I do the conect from the php page with this user. The do the conection with:

pg_pconnect(" host=one_host dbname=one_dbase user=one_user password=one_pass")

Some ideas?
Thanks in advance.

Ana