plpgsql refcursor

Hi all.

I'm having problems obtaining resultsets from a pgsql function, I've read the jdbc documentation, and read similar messages in the lists, but I still cannot make it work. Perhaps someone can see what's wrong with my code, because I can't find it

my plgpsql function is:
CREATE OR REPLACE FUNCTION usuarios_load(INTEGER) RETURNS REFCURSOR AS '
DECLARE
   result REFCURSOR;
BEGIN
   OPEN result FOR SELECT * FROM usuarios WHERE id=$1;
   RAISE NOTICE ''usuarios_load() -> %'', result;
   RETURN result;
END;
' LANGUAGE 'plpgsql';

my java code is:
conn.setAutoCommit(false);

cstmt=conn.prepareCall("{ ? = call usuarios_load( ? ) }");
cstmt.registerOutParameter(1, Types.OTHER);
cstmt.setInt(2, 33);
cstmt.execute();
rs=(ResultSet)stmt.getObject(1);
while (rs.next()) {
System.out.println(rs.getString(0)); << throws exception
}

the logs says:
2003-12-15 16:54:35 LOG:  statement: set datestyle to 'ISO'; select version(), case when pg_encoding_to_char(1) = 'SQL_ASCII' then 'UNKNOWN' else getdatabaseencoding() end;
2003-12-15 16:54:35 LOG:  statement: set client_encoding = 'UNICODE'
2003-12-15 16:54:35 LOG:  connection received: host=192.168.1.162 port=49948
2003-12-15 16:54:35 LOG:  connection authorized: user=sapiens database=franco
2003-12-15 16:54:35 LOG:  statement: begin;
2003-12-15 16:54:35 LOG:  statement: select * from  usuarios_load( 33 )  as result;
2003-12-15 16:54:35 LOG:  statement:  SELECT * FROM usuarios WHERE id= $1
CONTEXT:  PL/pgSQL function "usuarios_load" line 5 at open
2003-12-15 16:54:35 NOTICE:  usuarios_load() -> <unnamed portal 1>
2003-12-15 16:54:35 LOG:  statement: SELECT   $1
CONTEXT:  PL/pgSQL function "usuarios_load" line 14 at return
2003-12-15 16:54:35 LOG:  statement: SELECT typname FROM pg_catalog.pg_type WHERE oid = 1790
2003-12-15 16:54:35 LOG:  statement: FETCH ALL IN "<unnamed portal 1>"; << this is where exception is thrown
2003-12-15 16:54:35 LOG:  statement: commit;begin;
2003-12-15 16:54:35 LOG:  unexpected EOF on client connection


thanks in advance!