Not able to access schema functions and table...

Hi,

I have executed below queries.

CREATE SCHEMA mydb_schema AUTHORIZATION postgres;

GRANT ALL ON SCHEMA mydb_schema TO postgres;

REVOKE ALL ON SCHEMA mydb_schema FROM PUBLIC;
REVOKE ALL ON FUNCTION mydb_schema.readtable() FROM PUBLIC;

GRANT EXECUTE ON FUNCTION mydb_schema.readtable() to user1;

GRANT SELECT ON mydb_schema.test1 TO user1;

$ psql -h postgresqlhost.aus -d mydb -U user1
psql (8.4.1)
Type "help" for help.
user1=> select mydb_schema.readtable();
ERROR: permission denied for schema mydb_schema
user1=> select * from mydb_schema.test1;
ERROR: permission denied for mydb_schema
LINE 1: select * from mydb_schema.test1;
^
user1=>

Could anyone please tell me what is wrong here? *I want users to have only
select persions on tables of mydb_schema schema and function readtable
execute permissions for only few users(like above user1).*

Please let me know if there is any alternative way.

Thanks,
Dipti