manualresetevent.waitone is hanging

Question

I have a windows service with a timer. About 3 times a day the timer uploads files to different ftp servers. I set the timer, upload the files, then set the next time. This worked fine for a while, until I added another ftpserver for uploading files. When uploading to that ftpserver the project hangs at manualresetevent.waitone (even though the folder was uploaded) Here part of the code, let me know if more is needed.

Dim state As New FtpState
                    Dim request As FtpWebRequest = DirectCast(WebRequest.Create(target), FtpWebRequest)
                    request.Method = WebRequestMethods.Ftp.UploadFile

                    request.Credentials = mycredentials 

                    state.Request = request
                    state.FileName = fileName

                    ' Get the event to wait on.
                    waitObject = state.OperationComplete

                    ' Asynchronously get the stream for the file contents.
                    request.BeginGetRequestStream(New AsyncCallback(AddressOf EndGetStreamCallback), state)

                    ' Block the current thread until all operations are complete.
                    waitObject.WaitOne()

                    ' The operations either completed or threw an exception. 
                    If state.OperationException IsNot Nothing Then
                        Throw New Exception(state.OperationException.ToString)
                    Else

                        Publish.sendMail("Upload completed for filename:" & fileName & state.StatusDescription)
                    End If
                End If

This ftpserver works a little different than the others that I'm using and I'm not sure if thats the cause of the problem.

Here is the difference: I upload a zip folder (not just files) which can be quite large and soon after it's uploaded, it is being moved from that ftpserver.

(Whereas the other ftpservers leave the files on the ftpserver)

I think this problem only started once the zipfolder got larger.

I know that it is uploaded and then deleted from there.

So if the upload completed, why does it get stuck at waitone?

Here my endstreamcallback function

Private Shared Sub EndGetStreamCallback(ByVal ar As IAsyncResult)
    Dim state As ftpState = DirectCast(ar.AsyncState, ftpState)

    Dim requestStream As Stream = Nothing
    ' End the asynchronous call to get the request stream. 
    Try
        requestStream = state.Request.EndGetRequestStream(ar)
        ' Copy the file contents to the request stream. 
        Const bufferLength As Integer = 2048
        Dim buffer As Byte() = New Byte(bufferLength - 1) {}
        Dim count As Integer = 0
        Dim readBytes As Integer = 0
        Dim stream As FileStream = File.OpenRead(state.FileName)
        Do
            readBytes = stream.Read(buffer, 0, bufferLength)
            requestStream.Write(buffer, 0, readBytes)
            count += readBytes
        Loop While readBytes <> 0
        'Console.WriteLine("Writing {0} bytes to the stream.", count)
        ' IMPORTANT: Close the request stream before sending the request.
        requestStream.Close()
        ' Asynchronously get the response to the upload request.
        state.Request.BeginGetResponse(New AsyncCallback(AddressOf EndGetResponseCallback), state)
        ' Return exceptions to the main application thread. 
    Catch e As Exception
        Publish.sendMail("Could not get the request stream.")
        state.OperationException = e
        state.OperationComplete.[Set]()
        Return
    End Try

End Sub

' The EndGetResponseCallback method
' completes a call to BeginGetResponse.

   Private Shared Sub EndGetResponseCallback(ByVal ar As IAsyncResult)
    Dim state As FtpState = DirectCast(ar.AsyncState, FtpState)
    Dim response As FtpWebResponse = Nothing
    Try
        response = DirectCast(state.Request.EndGetResponse(ar), FtpWebResponse)
        response.Close()
        state.StatusDescription = response.StatusDescription
        ' Signal the main application thread that  
        ' the operation is complete.
        state.OperationComplete.[Set]()
        ' Return exceptions to the main application thread. 
    Catch e As Exception
        Publish.sendMail("Error getting response.")
        state.OperationException = e
        state.OperationComplete.[Set]()
    End Try
End Sub