Call to DBMS_SESSION.set_context throws 01031 Insuf. priv. error

Question

DBMS_SESSION.set_context has public synonym and has granted execute to public.
Why do I get insufficient privileges error when it's called from the 10g form or 10g db?

Answer 1

So is this an accurate reflection of how you have this set up?
ME_XE?create procedure my_test
  2  as
  3  begin
  4  dbms_session.set_context('MYCTX', 'VALUE1','HELLO WERLD');
  5  end;
  6  /
Procedure created.
Elapsed: 00:00:08.10
ME_XE?create or replace context myctx using my_test;
Context created.
Elapsed: 00:00:00.26
ME_XE?grant execute on my_test to test;
Grant succeeded.
--logged in as TEST user now
exec tubby.my_test;
PL/SQL procedure successfully completed.
Elapsed: 00:00:00.04
select sys_context('MYCTX','VALUE1') from dual;
SYS_CONTEXT('MYCTX','VALUE1')
HELLO WERLD
1 row selected.