Data Report is not refresh until i reload the program

The following is my code. I have set DE(Data Environment) = Nothing and Invoice (Report Name) = Nothing

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Code:

szSql = "select contract, DueDate, Amount, Cname, Csur From contract, ar_sub, customer where contract.custid = customer.custid and contract.contractno = ar_sub.contractno and "
szSql = szSql & "ar_sub.subid like '" & SubID & "' and "
szSql = szSql & "month(duedate) like '" & m & "' and "
szSql = szSql & "year(duedate) like '" & Year(Date) & "' "

Invoice.Sections("section2").Controls("lblSub").Caption = Sname
DE.Commands("Invoice").CommandText = szSql
Invoice.Show
Set Invoice = Nothing
Set DE = Nothing

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