[HELP] sending n receiving several picture using socket programming

[murid]

Sending Parts:

For var = i To x
                        Dim PACKET_SIZE As UInt16 = 4096
                        Dim ByteArray() As Byte ' Data buffer
                        filestream = New FileStream(at(z), FileMode.Open, FileAccess.Read)
                        Reader = New BinaryReader(filestream)
                        Writer = New BinaryWriter(clientSocke.GetStream) ' Get socket's stream
                        'send size of file
                        Writer.Write(CInt(filestream.Length))
                        'Send the file data
                        Do
                            'read data from file
                            ByteArray = Reader.ReadBytes(PACKET_SIZE)
                            'write data to Network Stream
                            Writer.Write(ByteArray)
                        Loop While ByteArray.Length = PACKET_SIZE
                        'make sure all data is sent
                        Writer.Flush()
                        z = z + 3
                    Next

NOTE : at(z) ---> arrayteks that's save filepath

Receiving Parts:

For var = i To x
                        Dim PACKET_SIZE As UInt16 = 4096
                        Dim Reader As BinaryReader
                        Dim ReadBuffer(PACKET_SIZE - 1) As Byte
                        Dim NData As Int32
                        Dim MStream As MemoryStream
                        Dim LData As Int32
                        Reader = New BinaryReader(clientSocket.GetStream)
                        ' Read Length of data (Int32)
                        NData = Reader.ReadInt32
                        MsgBox(NData.ToString)
                        ' Now comes the data, save it in a memory stream
                        MStream = New MemoryStream
                        While NData > 0
                            LData = clientSocket.GetStream.Read(ReadBuffer, 0, PACKET_SIZE)
                            MStream.Write(ReadBuffer, 0, LData)
                            NData -= LData
                            probar += 1
                            BackgroundWorker1.ReportProgress(probar)
                            Threading.Thread.Sleep(100)
                        End While
                        probar = 100
                        BackgroundWorker1.ReportProgress(probar)
                        Threading.Thread.Sleep(100)
                        SaveFile(arrayTeks(z), MStream.ToArray, False) 'Then
                        z = z + 3
                        probar = 0
                        BackgroundWorker1.ReportProgress(probar)
                    Next

NOTE: arrayteks(z) ----> file path that I use to save received picture file

problem :
I successfully received the 1st picture file, but, when it comes the 2nd picture mu program start to have an infinite loops...

any Idea ???

thanks before...