Stay tuned for more PS3 Hacks and PS3 CFW news, follow us on Twitter and be sure to drop by the PS3 Hacks and PS3 Custom Firmware Forums for the latest PlayStation 3 scene updates and homebrew releases!
It may be something to do with the firmware you are using. Some things don't work the same on 3.41 as 3.55. Maybe try the new hermes bum that was released for 3.41. I think I remember it said it has ftp build in it now. Would be easy enough to try it and see how it goes.
You must open dev_blind folder not dev_flash when you want to copy back.