For file downloads, this will be the name of the file to download. For file uploads, this will be the name of the uploaded
This parameter is initalized when the FileTransfer object is created.
FileName is the name of the file on the server running MobiLink. MobiLink will first search for this file in the userName
subdirectory and then in the root directory (the root download directory is specified via the MobiLink server's -ftr option,
and the root upload directory is specified via the -ftru option). FileName must not include any drive or path information,
or the MobiLink server will be unable to find it. For example, "myfile.txt" is valid, but "somedir\myfile.txt", "..\myfile.txt",
and "c:\myfile.txt" are all invalid.