1) Open up your WTF folder found in your root directory
2) Open Launcher.WTF with a text editor (like Notepad)
3) Change:
toSET accountType "LK"
4) Open up Config.wtf with a text editorSET accountType "CT"
5) Change:
toSET accounttype "LK"
6) Start downloading by opening Launcher.exeSET accounttype "CT"
If this doesn't work for you, you can download a mirrored version of the files:
expansion3.MPQ - 632.3 Mb
expansion3-speech-enUS.MPQ - 55.5 Mb
expansion3-locale-enUS.MPQ - 1.0 Mb
Enjoy!