The Public Test Realm (PTR) is the venue for the planned features (for future patches) for the MMORPG World of Warcraft and it's quite understandable that a good number of players would want to try it out. Along with the threads asking for premade characters, some players are also having problems starting PTR.

Mekeel from the WoW forums in Europe was having that very problem. She's given an error message everytime she tries to start the PTR WoW.exe file. Blizzard poster Shaantie was quick to come to the rescue. According to the blue poster, the patch file is working properly and the problem might lie in the player's file system.

First, make sure you have enough space on your disk to allow the patcher to work comfortably. After cleaning up your useless files (including the WoWTest folder and the PTR patch file), please close a maximum of applications and run a Scandisk followed by a Defrag on your disk. This is very, very long (especially for large disks) but very useful for your system. When this is done, restart windows, re download the PTR patch file and restart the patching process. For even more security before patching, you might want to launch the normal game and login, just to make sure the files in your World of Warcraft folder are not corrupt too, repair if necessary.

If you're still having problems, you should contact WoW technical support. They'll surely help you out.