¿Alguien sabe por qué recibo un error "tipo definido por el usuario no definido" en elFunction GetOutlookApp() As Outlook.Application al final de con este código?

Sub CreateAppointments()

Dim cell As Excel.Range
Dim rng As Excel.Range
Dim wholeColumn As Excel.Range
Dim startingCell As Excel.Range
Dim oApp As Outlook.Application
Dim tsk As Outlook.TaskItem
Dim wkbk As Excel.Workbook
Dim wksht As Excel.Worksheet
Dim lastRow As Long
Dim arrData As Variant
Dim i As Long

'iniciar aplicación de Outlook

Set oApp = GetOutlookApp
If oApp Is Nothing Then
  MsgBox "Could not start Outlook.", vbInformation
  Exit Sub
End If

'obtenga el rango de la hoja de trabajo en una matriz de una sola vez

Set wkbk = ActiveWorkbook
Set wksht = wkbk.ActiveSheet
Set wholeColumn = wksht.Range("B:B")
lastRow = wholeColumn.End(xlDown).Row - 2
Set startingCell = wksht.Range("B2")
Set rng = wksht,.Range(startingCell, startingCell.Offset(lastRow, 1))
arrData = Application.Transpose(rng.Value)

'recorrer la matriz y crear tareas para cada registro

For i = LBound(arrData, 2) To UBound(arrData, 2)
  Set tsk = oApp.CreateItem(olTaskItem)
  With tsk
    .DueDate = arrData(2, i)
    .Subject = arrData(1, i)
    .Save
  End With
Next I

End Sub

Function GetOutlookApp() As Outlook.Application
On Error Resume Next
Set GetOutlookApp = CreateObject("Outlook.Application")

End Function