VS 2010 [RESOLVED] InvalidCastException but is it?

Public Delegate Sub pullSubscriptionEventHandler(ByVal subscription As pullsubscription, ByVal folderEvent As folderEvent, ByVal itemEvents() As IEnumerable(Of ItemEvent), ByVal _emailService As ExchangeService)
 
 
Private Shared _events As EventHandlerList = Nothing
 
    Public Shared ReadOnly Property Events() As EventHandlerList
        Get
            If _events Is Nothing Then
                _events = New EventHandlerList()
            End If
            Return _events
        End Get
    End Property
 
Public Custom Event PullSubscriptionChange As pullSubscriptionEventHandler
        AddHandler(ByVal value As pullSubscriptionEventHandler)
            Events.AddHandler("PullSubscriptionChangeEvent", value)
        End AddHandler
 
        RemoveHandler(ByVal value As pullSubscriptionEventHandler)
            Events.RemoveHandler("PullSubscriptionChangeEvent", value)
        End RemoveHandler
 
        RaiseEvent(ByVal subscription As PullSubscription, ByVal folderEvent As FolderEvent, ByVal itemEvents() As IEnumerable(Of ItemEvent), ByVal _emailService As ExchangeService)
            CType(Events("PullSubscriptionChangeEvent"), pullSubscriptionEventHandler).Invoke(subscription, folderEvent, itemEvents, _emailService)
        End RaiseEvent
    End Event
 
 
 
Public Sub New()
     AddHandler PullSubscriptionChange, New pullSubscriptionEventHandler(AddressOf Me._emailWatcher.OnPullSubscriptionChangeEvent)
End Sub
 
 
 
 Private Sub OnTimedEvent(ByVal source As Object, ByVal e As ElapsedEventArgs)
        Dim notificationEvents As GetEventsResults = _subscription.GetEvents()
 
        If notificationEvents.AllEvents.Count > 0 Then
 
            Dim folderEvent As IEnumerable(Of FolderEvent) = notificationEvents.FolderEvents.Select(Function(p) p).Where(Function(p) p.FolderId.Equals(_trackFolderId)).ToList
            Dim itemEvents As IEnumerable(Of ItemEvent) = notificationEvents.ItemEvents.Select(Function(p) p).Where(Function(p) p.ParentFolderId.Equals(_trackFolderId)).ToList
 
            Dim signalChange As Boolean = folderEvent.Count > 0
 
            If signalChange Then
 
                Try
 
                    RaiseEvent PullSubscriptionChange(_subscription, folderEvent(0), itemEvents, _emailService)
 
                Catch ex As InvalidCastException
 
                    Debug.Print("Failed to cast itemEvents.")
 
                End Try
 
            End If
        Else
            Console.WriteLine("No changes have been detected.")
        End If
 
    End Sub
 
Public Sub OnPullSubscriptionChangeEvent(ByVal subscription As PullSubscription, ByVal folderEvent As FolderEvent, ByVal itemEvents() As IEnumerable(Of ItemEvent), Optional ByVal emailService As ExchangeService = Nothing)
        Dim handler As pullSubscriptionEventHandler = CType(MxsCacheDependency.Events("PullSubscriptionChangeEvent"), pullSubscriptionEventHandler)
        If (handler IsNot Nothing) Then
            Console.WriteLine("OnPullSubscriptionChangeEvent was fired with:" & vbCrLf & "{0} Subscription ID: {1}" _
                              & vbCrLf & " EventType: {2}" & vbCrLf & "on Thread: {3}.", _
                              DateTime.Now.ToString("h:mm:ss.fff"), subscription.Id, folderEvent.EventType, _
                              Threading.Thread.CurrentThread.ManagedThreadId)
 
            _pullSubscription = subscription
            _folderEvent = folderEvent
            _itemEvents = itemEvents
            If Not emailService Is Nothing Then
                _emailService = emailService
            End If
 
            GetItemChanges()
 
        End If
    End Sub

Dim itemEvents As IEnumerable(Of ItemEvent) = notificationEvents.ItemEvents.Select(Function(p) p).Where(Function(p) p.ParentFolderId.Equals(_trackFolderId)).ToList