actually this was happened to me the first time with a file from MU as well, I downloaded 10 files from MU around 400mb each except the last one which was 300mb something, and the problem hit me on that very last file. JD also freezed download from other hosts too when that particular download was active. I've managed to complete the file today and will try running download from other hosts to see if this is specific problem to MU, it seems to be fine now, will post again if the problem returned.