Auto Upload Problem

I have a bat script which suppose to upload a file to remote server however it keeps on failing. It seems to re-connect file however can not continue with upload.

"C:\Program Files\WinSCP\winscp.com" /script=upload.txt
option batch on
option confirm off
open usename@ftp -privatekey=private_key.ppk
put -resume E:\backup* /NewYork/
exit

Please see the log below

Authenticated.
Starting the session...
Reading remote directory...
Session started.
Active session: [1] user@ftp.upload.com
E:\Auto_FTP_Upload\Data\backup_20110131.zip | 23498 KiB | 58.5 KiB/s | binary | 8%
Host has not answered for more than 15 seconds. Still waiting...
Warning: Aborting this operation will close connection!
(A)bort: Abort
E:\Auto_FTP_Upload\Data\backup_20110131.zip | 23498 KiB | 28.1 KiB/s | binary | 8%
Terminated by user.
(A)bort, (R)econnect (5 s): Reconnect
Searching for host...
Connecting to host...
Authenticating...
Authenticating with pre-entered password.
Authenticated.
Starting the session...
Reading remote directory...
Session started.
E:\Auto_FTP_Upload\Data\backup_20110131.zip | 0 KiB | 0.0 KiB/s | binary | 0%
Cannot overwrite remote file '/backup_20110131.zip.filepart'.
Press 'Delete' to delete the file and create new one instead of overwriting it.
No such file or directory.
Error code: 2
Error message from server (en): File not found
Request code: 3
(D)elete, (A)bort, (R)etry, (S)kip, Ski(p) all: Abort

What is the SSH/SFTP server?

The server I am trying to connect is ftp.mrinetsource.com

OK, but do you know what server software does it run? Or post a complete log file.