SQL & PL/SQL

dear friends
i have a problem with utl_file package.

- Oracle 10gr2
- CENTos 4.0

The folder permissions are:
drwxrwx--- 2 oracle oinstall 4096 nov 29 17:40 test_UtlFileDir
...with that permisssion on the folder, the programmer done that file:
-rw-r--r-- 1 oracle oinstall 904 nov 29 17:40 example3.txt
everything is ok.

but....

I was done that yesterday in the night...
- i created a role and i assigned to that role execute utl_file
- then, i assigned this role to user TRAMITE
- revoke sys.utl_file from public.
Today
- i assigned to the same role the priv execute utl_smtp
- revoke sys.utl_smtp from public.

Here the actions:
*****************************************************************************************
SQL> SHO USER
USER es "SYS"

SQL> GRANT EXECUTE ON SYS.UTL_FILE TO ROLE_EXEC_UTL_FILE;

Concesión terminada correctamente.

SQL> GRANT ROLE_EXEC_UTL_FILE TO TRAMITE;

Concesión terminada correctamente.

SQL> REVOKE EXECUTE ON SYS.UTL_FILE FROM PUBLIC

Revocación terminada correctamente.

*****************************************************************************************

When my friend want to execute the package, oracle presents the next error:
=====================================================

0/0 PL/SQL: Compilation unit analysis terminated
5/19 PLS-00201: el identificador 'UTL_FILE' se debe declarar
5/19 PL/SQL: Item ignored
8/22 PL/SQL: SQL Statement ignored
8/53 PL/SQL: ORA-00942: la tabla o vista no existe
11/5 PLS-00320: la declaración de tipo de esta expresión está
incompleta o tiene un formato incorrecto
0/0 PL/SQL: Compilation unit analysis terminated
5/19 PLS-00201: el identificador 'UTL_FILE' se debe declarar
5/19 PL/SQL: Item ignored
8/22 PL/SQL: SQL Statement ignored
8/53 PL/SQL: ORA-00942: la tabla o vista no existe
11/5 PLS-00320: la declaración de tipo de esta expresión está
incompleta o tiene un formato incorrecto
=====================================================

When i looked for solution i saw this documento un metalink:Note:315283.1

...but i disagree about that, 'cause if i grant execute utl_file, utl_smtp to public, everyone can execute that Package.

Are there any other ways to assign "execute this packages" through role to users that i want without have any risk??

thanks for your answers, and apologize my english...

Cesar