Winsock File-Transfer problems

Hello,

I am sorry if I am asking stupid questions, but I searched the entire web but couldn't find out what was wrong about my VB6 code:

It's purpose is to send a file to a client, but the file get's damaged every time :(

Does anyone know what is wrong? Thank you very much!

-There is a Winsock control on my form called SendFile
-The var Ready becomes true when the SendData event is fired.

Client Code:

Open FileName For Binary As #Filenum
            If pos = 0 Then
                Put #Filenum, 1, Buffer
            Else
                Put #Filenum, pos, Buffer
            End If
            pos = pos + Len(Buffer)
        Close #Filenum

Server Code:

in top:
Private Const chunk = 8192
 
In event:
               Open Filename For Binary As #FileNum    
           
            FileLen = 0
            Do While Not EOF(FileNum)
                                                
                If FileLen + chunk > LOF(FileNum) Then
                    Dim Diff
                    Diff = LOF(FileNum) - FileLen
                    data = Input(Diff, #FileNum)
                    FileLen = FileLen + Diff
                Else
                    data = Input(chunk, #FileNum)
                    FileLen = FileLen + chunk
                End If
                
                Do Until Ready = True
                    DoEvents
                Loop
                SendFile.SendData data
                DoEvents
            Loop
        Close #FileNum