Group By ? Invalid Expression Error

[#1]

Hi All,

I am getting group by error ? how to resolve it...

MAin:

load

     MS_MAIN_ACNT_CODE,

  CUST_CODE1,

  OST_SUB_ACNT_CODE,

  OST_FC_ADJ_AMT,

  OST_FC_ORG_AMT,

  Sum(OST_FC_ORG_AMT-OST_FC_ADJ_AMT) as DebtorsOutStandingAmount,

  if(OST_DUE_DT<Today(),sum(OST_FC_ORG_AMT-OST_FC_ADJ_AMT)) as DebtorsOverdueAmount,

  CURR_CODE,

  OST_DOC_DT,

  OST_DUE_DT

Resident FT_OS

Group by CUST_CODE1;

DROP Table FT_OS;

[#2]

HI,

Debtors Outstanding Amount is Fine...

For Over Due Amount, I need to get Outstanding amount on from based on OST_DUE_DT Based on each & every transaction..