Problem with Tax account has not been defined for the selected tax code

Dear guys..

I have a problem with creating journal entry with DI API and message says "Tax account has not been defined for the selected tax code"

1. Set oJnl = oCompany.GetBusinessObject(SAPbobsCOM.BoObjectTypes.oJournalEntries)

2. oJnl.TaxDate = Now

3. oJnl.Memo = "Tax Invoice"

4. oJnl.Lines.ShortName = sBpAccCode ' BP Code

5. oJnl.Lines.Credit = sAngka ' Amount

6. oJnl.Lines.Add

7. oJnl.Lines.AccountCode = sBpAccCode ' Bp Code

8. oJnl.Lines.Debit = sTax ' Amount

9. oJnl.Lines.Add

10. oJnl.Lines.AccountCode = sTaxGLAcct ' Tax Acct Code

11. oJnl.Lines.Debit = DPP ' Amount

12. oJnl.Lines.Add

I supposed that i can't entry sBpAccCode in Line 7. I try to change in line 7 with sTaxGLAcct and so running well. But if i try entry via screen SBO with same posting, it's successfully saved.

What happen maybe in my above code??

Thanks

Rgds

Toro -