I'll toss out some advice (blind advice I guess
).
Make sure that your router has port-forwarding enabled.
Make sure your firewall is letting BT through.
Sometimes Seeds will choke you -- meaning they won't let you download. This could be because you don't have anything they want, or don't appear to have a good connection. Wait it out.
Some trackers won't let you download unless you register.
Sometimes you get random errors from the tracker. Wait it out.
I'll recommend Azureus over the standard client. It's never steered me wrong.