>Hi,
>
>Thank for your advise. However, after I tranfer my file,
>my application had to test that the file is successfully transfer to
>server side, then had to delete it on my local location. The server
>will not check it integrity.
>
>For transfer protocols, I think they work because both side of the
>transfer are same protocol which are monitoring the transfer, hence
>they can resend if any integrity of the file is detected.

What transfer protocol are you using in the dialer program? Perhaps file integrity is built in to the protocol and you can query a status flag of the dialer itself for your answer.