lo_creat problem?

Hi,

I don't know if this is a perl issue or not but here's the scenario:

Platform: Linux 2.2 kernel (Japanized)
Postgres: 7.03 (compiled with --with-perl and --enable-multibyte )
pgsql_perl: 1.90, 1.81

The problem is very simple. 
All i'm trying to do is to create a Large Object. However,

$conn->lo_creat( PGRES_INV_WRITE | PGRES_INV_READ );
$conn->lo_import ( 'some_filename' );

both return an OID of ZERO, no matter what I do.
It doesn't even return PGRES_InvalidOID on failure.

In fact, the lo_demo.pl, which came with pgsql_perl 1.9, didn't work
either. So I don't think it would be a problem on my script.

Is this a known issue? Is there a way around it?

Any help would be appreciated.
Thanks in advance,
--d