capturing errors

Hi,

I'm trying to capture the error from php to show an informative
message to the user but i haven't managed to get it...

i'm using pg_result_error_field() but when i print it i get nothing,
is there something i have to configure or what i'm doing bad.
attached a little php script for testing and here is the schema the
script is using (obviously the error i'm trying to catch here is
unique violation)
"""
create table t1_fk1(col1 integer primary key);
insert into t1_fk1 values(1);
"""
--
Atentamente,
Jaime Casanova
Soporte y capacitación de PostgreSQL
Asesoría y desarrollo de sistemas
Guayaquil - Ecuador
Cel. +59387171157