ORA-01031: insufficient privileges when try to alter index in the stored procedure.

I have grappled with this nasty "NO-NO" for quite a while, just cannot seem to get it to work. My goal is simple, try to rebuild the index in a procedure, which requires me to embed the "ALTER INDEX" inside the dynamic SQL.

Basic info here: oracle9i database, LINUX AS 2.1 (i don't think it matters though).

What I have tried:
Log in as the SCHEMA OWNER.

1. I have tested by calling "alter index <index_name> rebuild online compute statistics" in the sqlplus window , it worked fine.
2. the roles and sys privs this accout have are:
ROLE: DBA, CONNECT, RESOURCE.
SYSTEM PRIVS: create any index, alter any index, create any indextype, alter any indextype.
3. Then everytime, I execute the "exec cmdb_util.rebuild_all_indexes" . it threw me off with the ORA-01031.

Don't explain to me that ROLE is disabled in the stored procedure because I have all index related system privileges directly assigned.

Anyone, please chime in.....


---------My code is below, it's pretty simple, you can test by just copying and pasting.
CREATE OR REPLACE PACKAGE cmdb_util
AS
TYPE g_ind_cursor_type IS REF CURSOR;
PROCEDURE rebuild_all_indexes;
END;
/


PROCEDURE rebuild_all_indexes
AS

l_ind_name VARCHAR2(30);
g_ind_cursor g_ind_cursor_type;
BEGIN
      OPEN g_ind_cursor FOR 'select index_name FROM user_indexes where index_name NOT LIKE '||chr(39)||'SYS_%'||chr(39);
      FETCH g_ind_cursor INTO l_ind_name;
      LOOP
            EXIT WHEN g_ind_cursor%NOTFOUND;      
            execute immediate 'ALTER INDEX '||l_ind_name||' REBUILD ONLINE COMPUTE STATISTICS';            
            FETCH g_ind_cursor INTO l_ind_name;
      END LOOP;
      CLOSE g_ind_cursor;
      
END;

END cmdb_util;
/