procedure under SYSTEM is invalid - oracle

Question

I have a successfully compiled procedure under SYSTEM schema.
create or replace procedure get_file_list as
ns varchar2(1024);
cursor c_my_directory is
select directory_name, directory_path from all_directories where directory_path like '/home/oracle/EDI%';
begin
-- before generating the file list, the temporary table is deleted
delete from edi.temp_EDI_file_list;
for each_directory in c_my_directory loop
-- it reads the contents of my_directory into a table called X$FRBMSFT
sys.dbms_backup_restore.searchfiles (each_directory.directory_path, ns);
for each_file in (select fname_krbmsft as name from X$KRBMSFT) loop
insert into edi.temp_edi_file_list
values (each_directory.directory_name, each_file.name);
end loop;
end loop;
commit;
exception
when others then
raise_application_error (-20001,sqlcode || ' ' || sqlerrm);
end get_file_list;
[.. it was created under SYSTEM schema because I am not allowed to grant select on X$FRBMSFT to user "edi"].
I granted execute privilegies to user "edi" on this procedure.
[.. connected as SYSTEM, role SYSDBA, I executed grant execute on system.get_file_list to EDI;]
When I am trying to execute the procedure (execute system.get_file_list;) with user "edi" it return the error
PLS-00905: object SYSTEM.GET_FILE_LIST is invalid
Can someone, please, give me a hint about what am I doing wrong?
Thank you,

Answer 1

In the end I managed to create the procedure, with some help from the link provided by #APC.
... conected as SYSTEM
create or replace view file_list as select fname_krbmsft from X$KRBMSFT readonly;
create or replace procedure searchfiles (pattern in out nocopy varchar2, ns in out nocopy varchar2) authid definer as
begin
dbms_backup_restore.searchfiles(pattern, ns);
end searchfiles;
GRANT SELECT ON FILE_LIST TO EDI;
GRANT EXECUTE ON SEARCHFILES TO EDI;
... conected as EDI
create or replace procedure get_file_list as
ns varchar2(1024);
cursor c_my_directory is
select directory_name, directory_path from all_directories where directory_path like '/home/oracle/EDI%';
begin
-- before generating the file list, the temporary table is deleted
delete from edi.temp_EDI_file_list;
for each_directory in c_my_directory loop
-- it reads the contents of all directories into a table called X$FRBMSFT via procedure SEARCHFILES
sys.SEARCHFILES (each_directory.directory_path, ns);
-- it interogate the X$FRBMSFT via file_list view
for each_file in (select fname_krbmsft as name from sys.file_list) loop
insert into temp_edi_file_list
values (each_directory.directory_name, each_file.name);
end loop;
end loop;
commit;
exception
when others then
raise_application_error (-20001,sqlcode || ' ' || sqlerrm);
end get_file_list;
The difference was made by the way they were called the objects created with user SYSTEM. They were called with SYS.xxx instead of SYSTEM.xxx