You need to have installed a World of Warcraft Wrath of the Lich King game client, patch 3.3.5a
1) Go to your World of Warcraft folder.
2) Open the “Data” folder.
3) Open the “enUS” (or whichever language pack you’re using) folder.
4) Right click on the file named “realmlist.wtf”, open it with Notepad.
5) Replace ALL of the text in this file with the following:
set realmlist play.lachev.com
Please note that you must own a copy of the game (at least WotLK version), in order to play.