Setting My local folder as local storage and sync it trough my vb application without using DD

Hi greg i already made some improvement but, error keep haunting my program. so this is my code and the problem is this + $exception {"lookup_failed/closed/."} System.Exception {Dropbox.Api.ApiException<Dropbox.Api.Files.UploadSessionFinishError>}

Private Async Sub UploadToolStripMenuItem2_Click(sender As Object, e As EventArgs) Handles UploadToolStripMenuItem2.Click
        Dim C As New OpenFileDialog
        C.Title = "Choose File"
        C.Filter = "All Files (*.*)|*.*"
        If C.ShowDialog = Windows.Forms.DialogResult.OK Then
            Dim fileinfos = Path.GetFileName(C.FileName)
            Dim filetempat = Path.GetFullPath(C.FileName)
            Dim tempat As String = direktori.Text & "/" & fileinfos
            Await Upload(filetempat, tempat)

        End If
    End Sub
    Async Function Upload(localPath As String, remotePath As String) As Task
        Const ChunkSize As Integer = 4096 * 1024
        Using fileStream = File.Open(localPath, FileMode.Open)
            If fileStream.Length <= ChunkSize Then
                Await A.Files.UploadAsync(remotePath, body:=fileStream)
            Else
                Await Me.ChunkUpload(remotePath, fileStream, ChunkSize)
            End If
        End Using
    End Function

    Private Async Function ChunkUpload(path As [String], stream As FileStream, chunkSize As Integer) As Task
        Dim numChunks As Integer = CInt(Math.Ceiling(CDbl(stream.Length) / chunkSize))
        Dim buffer As Byte() = New Byte(chunkSize - 1) {}
        Dim sessionId As String = Nothing
        For idx As Integer = 0 To numChunks - 1
            Dim byteRead = stream.Read(buffer, 0, chunkSize)

            Using memStream = New MemoryStream(buffer, 0, byteRead)
                If idx = 0 Then
                    Dim result = Await A.Files.UploadSessionStartAsync(True, memStream)
                    sessionId = result.SessionId
                    kondisi.Text=byteRead
                Else
                    Dim cursor = New UploadSessionCursor(sessionId, CULng(CUInt(chunkSize) * CUInt(idx)))

                    If idx = numChunks - 1 Then
                        Dim fileMetadata As FileMetadata = Await A.Files.UploadSessionFinishAsync(cursor, New CommitInfo(path), memStream)
                        MessageBox.Show("Upload Complete")
                        Console.WriteLine(fileMetadata.PathDisplay)
                    Else
                        Await A.Files.UploadSessionAppendV2Async(cursor, True, memStream)
                        MessageBox.Show("Upload Failed")
                    End If
                End If
            End Using
        Next
    End Function