I had problems making an FTP connection to my Atspace account for a couple of weeks, preventing my webcam image from updating. Filezilla kept failing to connect, and the most information I was able to find about what was wrong was from Windows’ commandline ftp (yea, it’s horrible, I know), which kept saying ftp : connect :unknown error number (‘tuntematon virhenumero’ tai jotain sinne päin suomeksi).
Thanks to Juha, I finally realized it was PeerGuardian 2 blocking the connection. Perhaps the fact that they’ve done this is related to Atspace having problems with spyware opening browser windows with their front page. In any case, I uninstalled PG2 since it’s been a source of trouble before. But it hadn’t done this to me before, nor caused any problems in a while, which had lead to me completely forgetting about ever having installed it (like I said in the thread at Atspace’s support forums).