query run successfully in sql*plus but return 0 records affected in vb6

I've did a program using vb6 to connect to oracle9i, i can establish the connection, the problem is when i execute the query in oracle sql*plus, it can execute successfully, but when run in vb application, the records affected return 0, it do nothing for this query, any setting need to be done?
because this query insert and select to/from different database, i've created a database link for these 2 database, everything work find in oracle sql*plus.

thanks for help..

db.Open "Provider=OraOLEDB.Oracle.1;Persist Security Info=False;USER ID=max;PASSWORD=max;Data Source=oracledb"

sSQL = "INSERT INTO FWDINVOICE_DET_at_ORACLEAR (COMPANYCODE,BRANCHCODE,INVOICENO,JOBNO,CHARGECODE)" & _
" (SELECT FWDINVOICE_DET.COMPANYCODE,FWDINVOICE_DET.BRANCHCODE," & _
"

FWDINVOICE_DET.InvoiceNo,FWDINVOICE_DET.JobNo,FWDINVOICE_DET.ChargeCode" & _
" FROM FWDINVOICE_DET_at_ORACLEDB,FWDINVOICE_HD_at_ORACLEDB" & _
" Where FWDINVOICE_HD.CompanyCode = FWDINVOICE_DET.CompanyCode" & _
" AND FWDINVOICE_HD.BRANCHCODE=FWDINVOICE_DET.BRANCHCODE" & _
" AND FWDINVOICE_HD.INVOICENO=FWDINVOICE_DET.INVOICENO" & _
" AND ( FWDINVOICE_HD.CANCEL= 'Y' OR FWDINVOICE_HD.APPROVED='Y') AND "
sSQL = sSQL & oLib.SQLRangeDate("FWDINVOICE_HD.InvoiceDate", Format(dtDateFrom, "dd-MMM-yyyy"), Format(dtDateTo, "dd-MMM-yyyy")) sSQL = sSQL & ")"

sSQL = UCase(sSQL)
db.Execute sSQL Received on Wed Nov 29 2006 - 02:02:00 CST