a file field cannot be given a value.
on the update page, if a file has already been uploaded, the hidden filed should hold the file name from the database.
the hidden field is used when no new file is uploaded. it is used so that the original file name is not removed.
the hidden field should be bound to the file name column fgrom your recordset.
in the upload file behavior, bind the default file name setting to the hidden field.
this was, if no new file is selected the server file name variable will be populated with the original file name from the hidden field.
if a new file is selected, the server file name variable will be populated with the new file name and stored in the database.
Chrome and fire fox wont display the text box that holds selected file name, but that is only visual, the file will still be sent as part of the form.