@ Rick - I wonder if it would be worth logging into your router and changing the DNS Servers from your default ISP's to either Open DNS - 208.67.222.222 / 208.67.220.220 or Google's 8.8.8.8 / 8.8.4.4 and then do the same for the Network adapter you are using on your computer to see if the ISO will download.
If you do change them, then open a command prompt and run it as an administrator and enter -
ipconfig /flushdns
ipconfig /registerdns
exit (to close the cmd window)
Not sure if the latency would be crap though with you being in China but if you open a command prompt and enter ping with each of the Primary for Open DNS and then Google's, you can see how long it will take.
For Google for me from the UK I get an av. of 45ms and 44ms for Open DNS.
Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation. All rights reserved.
C:\Windows\system32>ping 8.8.8.8
Pinging 8.8.8.8 with 32 bytes of data:
Reply from 8.8.8.8: bytes=32 time=45ms TTL=53
Reply from 8.8.8.8: bytes=32 time=45ms TTL=53
Reply from 8.8.8.8: bytes=32 time=45ms TTL=53
Reply from 8.8.8.8: bytes=32 time=45ms TTL=53
Ping statistics for 8.8.8.8:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 45ms, Maximum = 45ms, Average = 45ms
C:\Windows\system32>ping 208.67.222.222
Pinging 208.67.222.222 with 32 bytes of data:
Reply from 208.67.222.222: bytes=32 time=44ms TTL=58
Reply from 208.67.222.222: bytes=32 time=44ms TTL=58
Reply from 208.67.222.222: bytes=32 time=45ms TTL=58
Reply from 208.67.222.222: bytes=32 time=44ms TTL=58
Ping statistics for 208.67.222.222:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 44ms, Maximum = 45ms, Average = 44ms
C:\Windows\system32>