Connecting to schema problems

Hi!
I'm very new in postgreSQL and i can't create a successfully connection to my schema.
My database:
database: dspace
schema: public
owner of dspace database: dspace

I'm using this connection:
host: 127.0.0.1:5432
username:dspace
password: ******

When I connected with pgAdmin III to dspace database the query "select * from item;" returns records.
The problem occurs when I use a php utility to be connected, and the above query fails.
With the same php settings a query like "select * from pg_tables;" isn't failed and returns records to php utility.

I tried "select * from public.item;" and "select * from dspace.public.item;" with no result.

Any help would be appreciated.
Thank you,
Panagiotis