Most likely this will be down to firewall or router configuration issues. However, you do need to tell folks a lot more about what your set up is.
So, as CCRDude asked – what hardware / operating system? What firewall software? What router? Wired or wireless connection? Which SoundBridge product? Version numbers for Firefly, iTunes, SoundBridge Firmware? I know you say latest, but these things can change, and what was the latest last week may not be latest now, etc. Where is the music itself stored? On the computer’s local hard drive, on a USB drive, or networked storage, or even on another computer?
Sorry for so many questions, but all of these and more are relevant and can make a difference – and providing this information will help people to ask you the right questions to be able help you fix this.
First debug question – can the SoundBridge access any internet radio stations? Your computer is not needed for this to work.