Android Question error while inserting record

    Dim sql_string,sql As String
    sql_string = "INSERT INTO GL " & _
                 "(fbook,faccode,fdesc,fplace,fitcu,fin1,ftype," & _
                 "famt,fq1,fq2,fq3,frate1,frate2,frate3,fgst1,fvat2,fnum1,fnum2,fnum3,fnum4,fnum5,fcamt,fcq1,fadd5,fadd6) VALUES "
    
    Dim sb As StringBuilder
    sb.Initialize
    
    Dim i,mbatch As Int
    i = 0
    Do While i <= record
        If i Mod 500 = 0 Then
            Sleep(0)
        End If
        
        sb.Remove(0,sb.Length)
        sb.Insert(0,sql_string)
        
        mbatch = i + 249
        Do While i <= mbatch And i <= record
            m = list1.Get(i)
        
            book         = m.Get("mbook")    '1
            accode         = m.Get("maccode")    '2
            desc         = m.Get("mdesc")    '3
            place        = m.Get("mplace")    '4
            itcu         = m.Get("mitcu")    '5
            in1          = m.Get("min1")        '6
            ftype         = m.Get("mtype")    '7
            amt            = m.Get("mamt")
            'amt          = Round2(m.Get("mamt"),2)        '8
            q1           = m.Get("mq1")        '9
            q2           = m.Get("mq2")        '10
            q3           = m.Get("mq3")        '11
            rate1          = m.Get("mrate1")    '12
            rate2        = m.Get("mrate2")    '13
            rate3        = m.Get("mrate3")    '14
            gst1         = m.Get("mgst1")    '15
            vat3         = m.Get("mvat3")    '16
            num1         = m.Get("mnum1")    '17
            num2         = m.Get("mnum2")    '18
            num3         = m.Get("mnum3")    '19
            num4         = m.Get("mnum4")    '20
            num5         = m.Get("mnum5")    '21
            camt         = m.Get("mcamt")    '22
            cq1         = m.Get("mcq1")        '23
            add5         = m.Get("madd5")    '24
            add6         = m.Get("madd6")    '25

            sb.Append($"(""$).Append(book).Append($"",""$).Append(accode).Append($"",""$)
            sb.Append(desc).Append($"",""$).Append(place).Append($"",""$)
            sb.Append(itcu).Append($"",""$).Append(in1).Append($"",""$)
            sb.Append(ftype).Append($"",""$).Append(amt).Append($"",""$)
            sb.Append(q1).Append($"",""$).Append(q2).Append($"",""$)
            sb.Append(q3).Append($"",""$).Append(rate1).Append($"",""$)
            sb.Append(rate2).Append($"",""$).Append(rate3).Append($"",""$)
            sb.Append(gst1).Append($"",""$).Append(vat3).Append($"",""$)
            sb.Append(num1).Append($"",""$).Append(num2).Append($"",""$)
            sb.Append(num3).Append($"",""$).Append(num4).Append($"",""$)
            sb.Append(num5).Append($"",""$).Append(camt).Append($"",""$)
            sb.Append(cq1).Append($"",""$).Append(add5).Append($"",""$)
            sb.Append(add6).Append($""),"$)
        
            i = i + 1
        Loop
        sql = sb.Remove(sb.Length-1,sb.Length).tostring
        year.ExecNonQuery(sql)
    Loop