[dnanian]

OK: that indicates that the destination of the backup isn't mounted, indeed. But it won't mount it if SD! is running and you click "Copy Now". The mount is part of an alias dereference that happens when settings are loaded (which is also what happens when you start SD!). So -- try to set things up the way you want. Then, quit. Restart SD! and it'll restore the source and destination, and *that* will mount the remote volume. If it prompts for your password, make sure you add things to the keychain.