http://forum.square-enix.com/ffxiv/t...09-19900-10045

That user had to turn off NetLimiter.

If you're using any kind of antivirus, security software, browser security software, download manager or tools like netlimiter, try turning them off and trying again. Might need reboot between.
Some programs need to really be shut down and not just "disabled".

BullGuard and ZoneAlarm in particular are known to cause problems.