Doesn’t work for me too. I’ve tried every possible combination: with and without http://, with and without proxy, with and without ports, disable firewall and antivirus and so on… It just doesn’t work.
I have another CD ripping program which uses freedb and that one works perfectly. So… must be a bug. Too bad, I really love MP3 media studio, but without a working cddb i’m not going to put my money into it.