Invalid UNICODE character sequence found(0xc000)

psql returns:

Invalid UNICODE character sequence found(0xc000) in a valid query.

Steps to reproduce:

1. createdb -E UNICODE mydbname.
2. create a table with some varchar inside, we will query on this field.
Example:

CREATE TABLE auth_role
(
rol_id int4 not null default
nextval('auth_rol_rol_id_seq'),
rol_name varchar(50) unique not null,
rol_enable boolean default true,

primary key(rol_id)
);

INSERT INTO auth_role(rol_name,rol_enable) VALUES ('admin',true);
INSERT INTO auth_role(rol_name,rol_enable) VALUES ('zorro',true);

3. run psql and write a select like this:

SELECT * FROM AUTH_ROLE WHERE ROL_NAME LIKE 'z%';

4. I got the error.

Comments:

If in the LIKE we don't use the 'z%' this query runs OK. Examples:

LIKE 'zo%' ---- OK returns 1 row.
LIKE 'r%' ---- OK returns 0 rows.
LIKE 'az%' ---- ERROR again (contains z%).

Version:
the "SELECT version();" returns:
PostgreSQL 7.3.4-RH on i386-redhat-linux-gnu, compiled by GCC
i386-redhat-linux-gcc (GCC) 3.3.2 20031022 (Red Hat Linux 3.3.2-1)

OS: Fedora Core 1

Please help. I think this is a bug, but I am not sure.

Best Regards,

Antonio Gallardo