Hmm, seems to be the only option regarding that.
Check out the Apple support forums, I dug up this reply:
Let's check a couple settings inside iTunes and see if they help. Open iTunes Preferences -> Advanced tab -> General tab -> try changing the "Streaming Buffer Size" to a different setting & try the radio again.
Also check QuickTime's Control Panel:
* exit iTunes
* open Windows Control Panel -> Quicktime entry
* uh-oh - I'm on my Mac, and I don't recall the new PC layout for this setting...
* OK, I think there is a "Streaming" tab in the QT panel, and in there set your line speed at or even just below your ISP's advertised download rate for your connection.
* try iTunes Radio again.
Do you Norton Internet Security running? Try disabling the "Internet Security" firewall for a few minutes. Better?
That's all I got. Hope that works.