If you're getting the message that Sunshine posted above SG.. in your case it's probably because you don't have permission -- but if you mail me your yahoo ID I'll add you to the list..
Ringo -- are you getting the same message Sunshine posted above? That's a yahoo briefcase page with a yahoo banner at the top and it has a link to sign in..
However.. if you're seeing the standard DNS error page that says "The page cannot be displayed" then you're seeing the same thing that I'm seeing right now because yahoo briefcase is broken half of the time -- if you just check back later it may, or may not work... I'm looking for alternatives at the moment... my Group is still open to anybody that wants to join and files are available there - but the bandwidth limitations limit you to, it seems, one download per day...if you attempt to download more it will say something like you don't have permission -- instead of actually telling you there is a download limit -- that would make sense so Yahoo won't do it.
access it here
if anyone has any other file sharing solutions that are controllable please let me know... it would have to support mp3 formats..