serienmail verschicken... was ist falsch?

Sub SendMessage()
Dim i As Integer
Dim objOutlook As Outlook.Application <<<--- ?? benutzerdef. typ nicht definiert?!?
Dim objOutlookMsg As Outlook.MailItem
Dim objOutlookRecip As Outlook.Recipient
Set objOutlook = CreateObject("Outlook.Application")
Set objOutlookMsg = objOutlook.CreateItem(olMailItem)
' sortierung hier einfügen
For i = 15 To 100
If Cells(2, i) = "" Then Exit Sub
With objOutlookMsg
Set objOutlookRecip = .Recipients.Add(Mahnung.Cells(2, i))
.Subject = Mahnung.Cells(3, 2)
.Body = Mahnung.Cells(3, 3)
.Importance = olImportanceHigh
objOutlookRecip.Resolve
.Send
End With
Next i
Set objOutlook = Nothing
End Sub