运行时错误9：下标超出范围

Question

我正在做这个员工休假数据库，我总是得到这个：

  

运行时错误9：下标超出范围。

这就是我的代码的样子。并且错误发生在指定的部分。

Private Sub cmdAdd_Click()

    Dim RowCount As Long
    Dim VLAbsenceUTwPay, VLAbsenceUTwoutPay, VLBalance As Single
    Dim SLAbsenceUTwPay, SLAbsenceUTwoutPay, SLBalance As Single

    If Me.Reg1.Value = "" Then
        MsgBox "Please enter the entry no.", vbExclamation, "Employee Data"
        Me.Reg1.SetFocus
    End If

    '-----VACATION LEAVE------
    VLAbsenceUTwPay = Reg9.Value * 0.00208333333
    VLAbsenceUTwoutPay = Reg10.Value * 0.00208333333
    VLBalance = (Reg11.Value + Reg8.Value) - (VLAbsenceUTwPay + VLAbsenceUTwoutPay)

    '-----SICK LEAVE------------
    SLAbsenceUTwPay = Reg12.Value * 0.00208333333
    SLAbsenceUTwoutPay = Reg13.Value * 0.00208333333
    SLBalance = (Reg14.Value + Reg8.Value) - (SLAbsenceUTwPay + SLAbsenceUTwoutPay)
    RowCount = Worksheets("Sheet1").Range("B8").CurrentRegion.Rows.Count ' <<< Error line
    With Worksheets("Sheet1").Range("B8")
        .Offset(RowCount, 0) = Me.Reg1.Value
        .Offset(RowCount, 1) = Me.Reg2.Value
        .Offset(RowCount, 2) = Me.Reg3.Value
        .Offset(RowCount, 3) = Me.Reg4.Value
        .Offset(RowCount, 4) = Me.Reg5.Value
        .Offset(RowCount, 5) = Me.Reg6.Value
        .Offset(RowCount, 6) = Me.Reg7.Value
        .Offset(RowCount, 7) = Me.Reg8.Value
        .Offset(RowCount, 8) = Me.Reg9.Value
        .Offset(RowCount, 9) = VLAbsenceUTwPay
        .Offset(RowCount, 10) = Me.Reg10.Value
        .Offset(RowCount, 11) = VLAbsenceUTwoutPay
        .Offset(RowCount, 12) = Me.Reg11.Value
        .Offset(RowCount, 13) = VLBalance
        .Offset(RowCount, 14) = Me.Reg12.Value
        .Offset(RowCount, 15) = SLAbsenceUTwPay
        .Offset(RowCount, 16) = Me.Reg13.Value
        .Offset(RowCount, 17) = SLAbsenceUTwoutPay
        .Offset(RowCount, 18) = Me.Reg14.Value
        .Offset(RowCount, 19) = SLBalance
        .Offset(RowCount, 20) = Me.Reg15.Value
    End With

End Sub