Range().Value Problem

Private Sub CommandButton1_Click()
Dim a As String
Dim b As Integer
Dim c As Integer
Dim d As String
Dim e As Integer
Dim f As Integer
Dim Index As Integer
a = Mid(TextBox1.Text, 1, 1)
b = Mid(TextBox1.Text, 2, 2)
c = Asc(a) - 64
d = Mid(TextBox2.Text, 1, 1)
e = Mid(TextBox2.Text, 2, 2)
f = Asc(d) - 64
With Range(Cells(b, c), (Cells(e, f)))
If Range(Cells(b, c), (Cells(e, f))).Value = "" Then
If Range(Cells(b, c), (Cells(e, f))).Rows.Count = 5 Or _
Range(Cells(b, c), (Cells(e, f))).Columns.Count = 5 Then
.Value = "#"
.Font.Bold = True
.Interior.Color = vbYellow
Else
MsgBox "Bitte Abstand von 5 Zeilen/Spalten wählen", vbOKOnly &  vbInformation, " _
Hinweis"
Exit Sub
End If
Else
MsgBox "Diese Zelle ist bereits belegt", vbOKOnly & vbInformation, "Hinweis"
Exit Sub
End If
End With
Range(Cells(b, c), (Cells(e, f))).Select
For Index = xlEdgeLeft To xlEdgeRight
With Selection.Borders(Index)
.LineStyle = xlDouble
.Weight = xlThick
End With
Next Index
End Sub