Strange Errors when partition table in 9.2.0.4

Hi all,
  I tried partition table with oracle 9.2.0.4 64 bit on AIX. But I'm not lucky ! I hope some receive some helps.

  I have a table with about 10 million records. With this table, already exist :

    + two triggers,
    + five indexes,
    + two constraints.
    + some synonyms.

  My original table is look like:

  table_A(
    a_id number not null,
    a_value number default 1,
    a_date date defaut sysdate,
    ......
  );

  I did steps follows:

  1. I created table with same structure:

              create table_A_ref(

    a_id number not null,
    a_value number default 1,
    a_date date defaut sysdate,
    ......
  )

Partition by range(a_date)
(
  partition P08152008 values less than (to_date('15/10/2009','DD/MM/YYYY')),