We need more info about your system and your network configuration.
I am running windows vista 32 bit with service pack 2. I am also getting a 403 error when I try to download from creative cloud. I am connecting via a cable modem and I am not having any issues with any other services.
Can you restart the machine in "safe mode with networking" and then check.
Press "F8" while restarting , and then choose that option.
me too - same problem
Windows 7 64-bit SP1 - no problems on any other connections ...