Oracle 11g merge statement not working properly

Question

HI I have recently my oracle version to 11.2.0.3 -64 bit . My merge statement is geeting failied saying that invlid identfier at line number 18    
MERGE INTO peer_index indx        USING staging.stg_peer_filing stg          ON (indx.peer_element_code = stg.fund_code                and indx.index_effective_date = trunc(stg.pricing_date))        WHEN MATCHED THEN UPDATE          SET indx.filing_date = trunc(stg.filing_date),            indx.reported_net_assets = stg.net_assets,            indx.active_flag = 'N',            indx.parent_index_code = NULL,            indx.update_datetime = systimestamp,            indx.last_update_user_id = user        WHEN NOT MATCHED THEN INSERT         (index_code, peer_element_code, filing_date, index_effective_date,          reported_net_assets, active_flag          )        VALUES         ((SELECT pe.index_code_prefix || to_char(stg.pricing_date,'MMRR')           FROM fi_benchmark.peer_element pe           WHERE pe.peer_element_code = stg.fund_code),          stg.fund_code, trunc(stg.filing_date), trunc(stg.pricing_date),          stg.net_assets, 'N'         );
please help why this is happening .Same query works fine in 10g .

Answer 1

which line is the line that has the error?
merge INTO peer_index indx
USING staging.stg_peer_filing stg
ON (indx.peer_element_code = stg.fund_code AND indx.index_effective_date = Trunc
(stg.pricing_date))
WHEN matched THEN
  UPDATE SET indx.filing_date = Trunc(stg.filing_date),
             indx.reported_net_assets = stg.net_assets,
             indx.active_flag = 'N',
             indx.parent_index_code = NULL,
             indx.update_datetime = systimestamp,
             indx.last_update_user_id = USER
WHEN NOT matched THEN
  INSERT (index_code,
          peer_element_code,
          filing_date,
          index_effective_date,
          reported_net_assets,
          active_flag )
  VALUES ((SELECT pe.index_code_prefix
                  || To_char(stg.pricing_date, 'MMRR')
           FROM   fi_benchmark.peer_element pe
           WHERE  pe.peer_element_code = stg.fund_code),
          stg.fund_code,
          Trunc(stg.filing_date),
          Trunc(stg.pricing_date),
          stg.net_assets,
          'N' );