I use Mac as well and I think that might be part of the reason I have trouble on DIME too -- the firewalls have firewalls!
To use the Radiohub with Mac you want to download the client Direct Connect <strong>Jucy</strong>. Once it's installed, simply open it, set up the download directories (where the files will be shared and stored -- many users organize their files similarly by artists and then by year) and then connect to the Hub.
I'm a little hazy on how to connect to the Hub because I only did one time it a while ago and it's been smooth sailing ever since. Unless I'm mistaken, it's like this:
There may be other configurations to modify (for me, I have to use passive Mode under Connection Settings). If none of this works let me know and I'll ask around a little later to clarify how to connect.
Radiohub works beautifully on Mac! It's easier to set up than it seems. If I can do it then anyone can :)
The client to run on Mac is called Jucy [http://jucy.eu/]. Once it's downloaded and opened, go to Action -> Quick Connect -> input 216.144.241.21 and that should get you up and running.
I might be mistaken on how to connect to the Hub. Once you're connected you're automatically logged on when you open Jucy so I haven't had to connect manually since day 1. If you can't get it going send me a PM.