I'm having the same issue, and I'v ebeen having it for quite some time now. Running SL 2.6.3.227447 on Mac OSX Snow Leopard (10.6.6). When I upgraded to this viewer, I can't log in. I know everything is correct. I keep getting the "DNS error" message.
I can log in just fine with Phoenix.
There's lots of complaints about this issue, and all I can find is 1) it's a Mac only error and 2) nothing's been done about it yet. Which is quite annoying.