"Server did not accept the request (replied HTTP status; 200, expected 206)" message

This may happen due to different reasons. Some of them may be:

1) An anti-virus application may be blocking/filtering the download. Lower the anti-virus settings or disable the antivirus during the download.
2) Your internet service provider may use a built-in security service, which detects suspicious sites (and our prices are suspiciously low indeed) and checks if they are containing viruses, trojans, worms and etc. It probably filtered your download domain and caused problems to the download manager when it tried to continue downloading.