Can you try to disable Norton suite anyway?
I recently installed Windows 7 pro 64 bit and then installed WinSCP version 4.2.8 (build 818) to connect to a certain ftp site. When I try to connect, it consistently gives me an error saying 'server unexpectedly closed network connection'. I know that the ftp site is up and running because I verified that from a different machine running windows XP.
port is 22, protocol is sftp.
Earlier I used to have windows vista 32 bit and was able to connect to that same site successfully. Don't remember the WinSCP version I had earlier.
I also have Norton Security Suite running on my machine but I had this running on windows vista as well and everything worked fine.
Any help is greatly appreciated.