Hi Gavin, sometimes the streams are just a pain and timeout (we dont know why), you will find that one day they work and the next they wont, thats why we put multiple slots in there as a fall-back. also some networks/routers are a problem too, for instance I have a radio url that works in my house (talk radio) but wont work on my man-cave jukebox in my shed (connected with wifi).
Ok, first think to ask is are you using the default stream urls that were already installed at setup, or have you input new urls yourself ?.
Are you connected directly to your router ?, wireless or wired ?
Steve