"WSASTARTUP not yet performed" indicates one of the following is likely:
[ul][li] The WinSock DLLs are damaged on your system. (Unless WinSock DLLs, or things pretending to be them, have been placed into the Opus directory, this would probably affect other applications, so may be unlikely if other FTP clients seem to work OK.)
[li] A firewall, antivirus or similar piece of software is blocking Opus from making WinSock / networking calls.
[li] A 3rd party shell extension that gets loaded into Opus (and Explorer, File Open dialogs, etc.) is uninitialising WinSock, possibly due to a bug. (e.g. If the extension initialises it once, then un-initialises it twice, it will break the main initialisation.) Extensions related to cloud storage and online version control would be most likely to do this. ShellExView can be used to see which extensions are installed on your machine and disable them. You need to fully exit Opus (via File / Exit Directory Opus, not just by closing all open windows) and restart it for changes made with ShellExView to take effect.[/li][/ul]