Same situation here... but I think it's not an Apple Issue.
I found a problem really similar to this in 2008 with the DNS-313 and the old Leopard O.S.
Have a look at this thread (in this thread I am "tourniquet"):
http://forums.macrumors.com/archive/index.php/t-554245.html
The problem was really similar because with the finder you couldn't navigate but with the terminal (or with muCommander) you had no problem!
As you can see, the problem was that the Finder couldn't manage the "Unix Extensions" option, set to ON in the Samba Server on the DNS-313 (we had the firmware 1.0 then).
D-Link solved the issue later, with a firmware upgrade that disabled this "Unix Extensions" option so... couldn't it be possible that now Lion require this option to be set to ON again?!?!
I will try this evening (10 hours from now, I'm Italian) enabling the unix extensions on the Samba Server of the DNS-313 (gaining an access to the 313 by telnet) and I will let you know if I sort this issue out.
Greetings
Dave
P.S. My "english" *****... sorry... 🙂