MailSystem.Net: Fetching email that caused newmessagerecieved event to fire

MailSystem.Net: Fetching email that caused newmessagerecieved event to fire

I'm new using this component so bear with me. In short, I am trying to
capture the email that caused the newmessagerecieved event to fire. Here
is my code, is there anything obviously wrong that would cause this to
fail? It seems to me, through debugging, that it is failing when it sets
tempinbox to INBOX. Why is this?
Imports System.ComponentModel
Imports ActiveUp.Net.Mail
Public Class Form1
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles
MyBase.Load
Application_Start()
End Sub
Private Sub Application_Start()
Dim worker = New BackgroundWorker()
AddHandler worker.DoWork, AddressOf StartIdleProcess
If worker.IsBusy Then
worker.CancelAsync()
End If
worker.RunWorkerAsync()
End Sub
Dim _imap As Imap4Client
Private Sub StartIdleProcess(sender As Object, e As DoWorkEventArgs)
If _imap IsNot Nothing AndAlso _imap.IsConnected Then
_imap.StopIdle()
_imap.Disconnect()
End If
_imap = New Imap4Client()
_imap.ConnectSsl("imap.gmail.com", 993)
_imap.Login("user@gmail.com", "pass")
Dim inbox = _imap.SelectMailbox("INBOX")
AddHandler _imap.NewMessageReceived, AddressOf NewMessageReceived
inbox.Subscribe()
_imap.StartIdle()
End Sub
Private Sub NewMessageReceived(source As Object, e As
NewMessageReceivedEventArgs)
Dim _tempimap As Imap4Client = source
Dim tempinbox = _tempimap.SelectMailbox("INBOX")
Dim first As Integer = tempinbox.FirstUnseen
Dim email As Message = tempinbox.Fetch.MessageObject(first + 1)
MsgBox(email.BodyHtml.ToString)
End Sub
End Class