Try turning on some debug options from File>FTP>Default Options, Debug tab : "Log SlickEdit proxy events", "Verbose ssh", "Save log to ftplog???.log", "Time stamp on log entries", "Save vsproxy debug to vsproxy.log". Attempt the connection, get the problem, abort (big red button) the connection. Give us the following files:
'ftplog000.log' from your config-directory
'vsproxy.log' from your %TEMP% directory
++rodney