Issues enumerating and outputting items in outlook's sent items folder - vb.net

Question

As the title says, I'm having issues with enumerating and outputting item in my sent items folder in outlook. Specifically I'm looking for sent tasks. It keeps telling me there's nothing in the folder, when there is. The code is:
Private Sub GetSentTasks(objApp As Microsoft.Office.Interop.Outlook.Application)
Dim objNS As Outlook.NameSpace = objApp.GetNamespace("MAPI")
Dim folder As Outlook.MAPIFolder = _
objNS.GetDefaultFolder( _
Outlook.OlDefaultFolders.olFolderSentMail)
Dim searchCriteria As String = "[MessageClass] = 'IPM.TaskRequest'"
Dim strBuilder As StringBuilder = Nothing
Dim counter As Integer = 0
Dim taskItem As Outlook._TaskItem = Nothing
Dim folderItems As Outlook.Items = Nothing
Dim resultItem As Object = Nothing
Dim TTDcounter As Integer = 0
Try
folderItems = folder.Items
folderItems.IncludeRecurrences = True
If (folderItems.Count > 0) Then
resultItem = folderItems.Find(searchCriteria)
If Not IsNothing(resultItem) Then
strBuilder = New StringBuilder()
Do
If (TypeOf (resultItem) Is Outlook._TaskRequestItem) Then
counter += 1
taskItem = resultItem
'If taskItem.Categories = "TTD" Then
TTDcounter += 1
Dim listarray() As String = {taskItem.Delegator, taskItem.Subject, taskItem.DueDate, stripEstComp(taskItem.Body.ToString())}
taskPaneControl3.ListView1.Items.Add(TTDcounter).SubItems.AddRange(listarray)
'End If
End If
Marshal.ReleaseComObject(resultItem)
resultItem = folderItems.FindNext()
Loop Until IsNothing(resultItem)
End If
End If
If Not IsNothing(strBuilder) Then
Debug.WriteLine(strBuilder.ToString())
Else
Debug.WriteLine("There is no match in the " + _
folder.Name + " folder.")
End If
Catch ex As Exception
System.Windows.Forms.MessageBox.Show(ex.Message)
Finally
If Not IsNothing(folderItems) Then Marshal.ReleaseComObject(folderItems)
End Try
End Sub