File unavailable (e.g., file not found, no access).

I'm having a hard time with this thing.  Which file is it referring to?  The file it's going to upload to the remote server?  Or, is the the path to where it's supposed to write the file on the remote server?   The files that are supposed to be transferred to a remote server are at the moment sitting on the root of my site.  Here's the error: 
[WebException: The remote server returned an error: (550) File unavailable (e.g., file not found, no access).]
System.Net.FtpWebRequest.SyncRequestCallback(Object obj) +321
System.Net.FtpWebRequest.RequestCallback(Object obj) +19
System.Net.CommandStream.Abort(Exception e) +163
System.Net.FtpWebRequest.FinishRequestStage(RequestStage stage) +453
System.Net.FtpWebRequest.GetRequestStream() +880
upload2.btnUploadFile_Click(Object sender, EventArgs e) +140
System.Web.UI.WebControls.Button.OnClick(EventArgs ...