You may be suffering from 'contention'.
I.E. all the other users on the same 'local loop' are also trying to download music, and there is not enough bandwith to go round.
I would try it again at about two in the morning, when most of the others will be asleep in bed, and if it's OK then, thats the problem.
Or try click here to get a 'test' of your conenction. It might be the place you are getting the music from is not able to 'send it out' fast enough.