Just posting as I have just returned to WOW and had an issue when trying to login. I was getting a battle.net error #114 upon login.
Apparently there is an issue with DNS server resolution only from Southeast Asia region, which includes Japan, Australia, and New Zealand, and only for some ISP's. I happen to be on the Telstra network.
After some trolling around I found the fix: http://us.battle.net/wow/en/forum/topic/7709862059
I set my DNS to the Google DNSFor IPv4: 126.96.36.199 and 188.8.131.52. I then went to windows command prompt and flushed DNS cache. This is done by typing ipconfig /flushdns. Once the message pops up saying DNS resolver cache has been flushed, close the command prompt and launch the game.
Just thought id post this as there are a lot of different fixes floating around but this is the one that worked for me and I live in Australia.