PLS-00201: identifier 'SYS.DBMS_PIPE' must be declared

I'm getting errors when I compile this procedure.

create or replace procedure send_message
(v_message in varchar2)
is s integer;
begin
dbms_pipe.pack_message(v_message);
s:=dbms_pipe.send_message('DEMO_PIPE');
if s<>0
then raise_application_error(-20200,'ERROR'||to_char(s)||'sending on pipe');
end if;
end send_message;
 
 The errors are ..
   PLS-00201: identifier 'SYS.DBMS_PIPE' must be declared
   PL/SQL: Statement ignored
   PL/SQL: Statement ignored
   PLS-00201: identifier 'SYS.DBMS_PIPE' must be declared
So whats wrong? Thanks

 

Resolvent：

sql>connect sys as sysdba
sql>password: change_on_install
sql> grant execute on dbms_pipe to public;
sql>create public synonym dbms_pipe for dbms_pipe;（if the synonym doesn't exist）
sql>conn scott/tiger
sql>execute the package

 

ps：the all package execute privilege is included in role EXECUTE_CATALOG_ROLE

 

reference：http://www.experts-exchange.com/Databases/Oracle/Q_20538262.html