1) How do I access the unamnaged VDS windows server by FTP?
You would need to install an FTP server to do this. We talk more about it here: viewtopic.php?f=46&t=4268
2) I have installed a Homefront server, but on launch I get erro.r:
Failed to load Steam ServiceServiceStart: failed to start
This one can be ignored -- it's harmless and always shows.