Ora-03113: end-of-file on communication channel

I have a view see the code attached: The view works fine..Select * from VIEW retrieves record. But when I use the same view in a merge statement to update/insert a table..I get the following error:

ORA-03113:End of communication channel

Cannot understand why? The view uses "WITH CLAUSE" statment..For sometime I thought using "WITH CLAUSE" may be causing this error. Apparently this is not since I was able to execute the merge statement with another simple view using WITH clause..

Can somebody help me if you have come across the similar problem..

Thanks,
Girish

MERGE
INTO
  DW_REWARD_MNTHLY_AGG DW_REWARD_MNTHLY_AGG
USING
  (SELECT
  TO_NUMBER ( DW_REWARD_MNTHLY_AGG_VW.CALENDAR_MONTH_DW_ID )/* EXPRESSION.OUTGRP1.CALENDAR_MONTH_DW_ID */ CALENDAR_MONTH_DW_ID,
  DW_REWARD_MNTHLY_AGG_VW.INVITED_USER_CNT INVITED_USER_CNT,
  DW_REWARD_MNTHLY_AGG_VW.ENROLLED_USER_CNT ENROLLED_USER_CNT,
  DW_REWARD_MNTHLY_AGG_VW.TRANS_CNRM_MTH_CNT TRANS_CNRM_MTH_CNT,
  DW_REWARD_MNTHLY_AGG_VW.TRANS_CNCL_MTH_CNT TRANS_CNCL_MTH_CNT,
  DW_REWARD_MNTHLY_AGG_VW.TKT_SALE_CNRM_MTH_AMT TKT_SALE_CNRM_MTH_AMT,
  DW_REWARD_MNTHLY_AGG_VW.TKT_SALE_CNCL_MTH_AMT TKT_SALE_CNCL_MTH_AMT,
  DW_REWARD_MNTHLY_AGG_VW.TKT_CNRM_MTH_CNT TKT_CNRM_MTH_CNT,
  DW_REWARD_MNTHLY_AGG_VW.TKT_CNCL_MTH_CNT TKT_CNCL_MTH_CNT,
  DW_REWARD_MNTHLY_AGG_VW.TOT_COST_CNRM_MTH_AMT TOT_COST_CNRM_MTH_AMT,
  DW_REWARD_MNTHLY_AGG_VW.TOT_COST_CNCL_MTH_AMT TOT_COST_CNCL_MTH_AMT,
  DW_REWARD_MNTHLY_AGG_VW.ISSUED_DISCNT_ISSUED_MTH_AMT ISSUED_DISCNT_ISSUED_MTH_AMT,
  DW_REWARD_MNTHLY_AGG_VW.REEDEMED_DISCNT_ISSUED_MTH_AMT REEDEMED_DISCNT_ISSUED_MTH_AMT,
  DW_REWARD_MNTHLY_AGG_VW.DW_CREATED_DTTM DW_CREATED_DTTM,
  DW_REWARD_MNTHLY_AGG_VW.DW_LASTUPDATE_DTTM DW_LASTUPDATE_DTTM
FROM
  DW_REWARD_MNTHLY_AGG_VW  DW_REWARD_MNTHLY_AGG_VW
  )
    MERGE_SUBQUERY
ON (
  DW_REWARD_MNTHLY_AGG.CALENDAR_MONTH_DW_ID = MERGE_SUBQUERY.CALENDAR_MONTH_DW_ID
   )
  
  WHEN NOT MATCHED THEN
    INSERT
      (DW_REWARD_MNTHLY_AGG.CALENDAR_MONTH_DW_ID,
      DW_REWARD_MNTHLY_AGG.INVITED_USER_CNT,
      DW_REWARD_MNTHLY_AGG.ENROLLED_USER_CNT,
      DW_REWARD_MNTHLY_AGG.TRANS_CNRM_MTH_CNT,
      DW_REWARD_MNTHLY_AGG.TRANS_CNCL_MTH_CNT,
      DW_REWARD_MNTHLY_AGG.TKT_SALE_CNRM_MTH_AMT,
      DW_REWARD_MNTHLY_AGG.TKT_SALE_CNCL_MTH_AMT,
      DW_REWARD_MNTHLY_AGG.TKT_CNRM_MTH_CNT,
      DW_REWARD_MNTHLY_AGG.TKT_CNCL_MTH_CNT,
      DW_REWARD_MNTHLY_AGG.TOT_COST_CNRM_MTH_AMT,
      DW_REWARD_MNTHLY_AGG.TOT_COST_CNCL_MTH_AMT,
      DW_REWARD_MNTHLY_AGG.ISSUED_DISCNT_ISSUED_MTH_AMT,
      DW_REWARD_MNTHLY_AGG.REEDEMED_DISCNT_ISSUED_MTH_AMT,
      DW_REWARD_MNTHLY_AGG.DW_CREATED_DTTM,
      DW_REWARD_MNTHLY_AGG.DW_LASTUPDATE_DTTM)
    VALUES
      (MERGE_SUBQUERY.CALENDAR_MONTH_DW_ID,
      MERGE_SUBQUERY.INVITED_USER_CNT,
      MERGE_SUBQUERY.ENROLLED_USER_CNT,
      MERGE_SUBQUERY.TRANS_CNRM_MTH_CNT,
      MERGE_SUBQUERY.TRANS_CNCL_MTH_CNT,
      MERGE_SUBQUERY.TKT_SALE_CNRM_MTH_AMT,
      MERGE_SUBQUERY.TKT_SALE_CNCL_MTH_AMT,
      MERGE_SUBQUERY.TKT_CNRM_MTH_CNT,
      MERGE_SUBQUERY.TKT_CNCL_MTH_CNT,
      MERGE_SUBQUERY.TOT_COST_CNRM_MTH_AMT,
      MERGE_SUBQUERY.TOT_COST_CNCL_MTH_AMT,
      MERGE_SUBQUERY.ISSUED_DISCNT_ISSUED_MTH_AMT,
      MERGE_SUBQUERY.REEDEMED_DISCNT_ISSUED_MTH_AMT,
      MERGE_SUBQUERY.DW_CREATED_DTTM,
      MERGE_SUBQUERY.DW_LASTUPDATE_DTTM)
  WHEN MATCHED THEN
    UPDATE
    SET
                  INVITED_USER_CNT = MERGE_SUBQUERY.INVITED_USER_CNT,
  ENROLLED_USER_CNT = MERGE_SUBQUERY.ENROLLED_USER_CNT,
  TRANS_CNRM_MTH_CNT = MERGE_SUBQUERY.TRANS_CNRM_MTH_CNT,
  TRANS_CNCL_MTH_CNT = MERGE_SUBQUERY.TRANS_CNCL_MTH_CNT,
  TKT_SALE_CNRM_MTH_AMT = MERGE_SUBQUERY.TKT_SALE_CNRM_MTH_AMT,
  TKT_SALE_CNCL_MTH_AMT = MERGE_SUBQUERY.TKT_SALE_CNCL_MTH_AMT,
  TKT_CNRM_MTH_CNT = MERGE_SUBQUERY.TKT_CNRM_MTH_CNT,
  TKT_CNCL_MTH_CNT = MERGE_SUBQUERY.TKT_CNCL_MTH_CNT,
  TOT_COST_CNRM_MTH_AMT = MERGE_SUBQUERY.TOT_COST_CNRM_MTH_AMT,
  TOT_COST_CNCL_MTH_AMT = MERGE_SUBQUERY.TOT_COST_CNCL_MTH_AMT,
  ISSUED_DISCNT_ISSUED_MTH_AMT = MERGE_SUBQUERY.ISSUED_DISCNT_ISSUED_MTH_AMT,
  REEDEMED_DISCNT_ISSUED_MTH_AMT = MERGE_SUBQUERY.REEDEMED_DISCNT_ISSUED_MTH_AMT,
  DW_CREATED_DTTM = MERGE_SUBQUERY.DW_CREATED_DTTM,
  DW_LASTUPDATE_DTTM = MERGE_SUBQUERY.DW_LASTUPDATE_DTTM;