In case this helps anyone:
I had this ~20mb then stopping problem for both my laptop and desktop at home (laptop using windows 7 the other an iMac running WinXP with bootcamp). My router is using the google dns server (all 7s as I recall) which I didn’t expect to be a problem – but I admit I never changed it.
Flushing DNS in a teminal with:> ipconfig /flushdns
didn’t fix the problem but like most of you I was getting ~20mb with each restart so I just kept restarting, eventually I got there and everything ran normally from there on (the light at the end of the tunnel for some of you perhaps?). Though during my many restarts (prob about 100 for the ~15 files) occasionally the client wouldn’t reconnect and start downloading, when this happened it just froze, but I found that if you flush the DNS (with the command above) then the next restart should connect and get the next ~20mb chunk.
Good luck