The T.King interfaces install differently from normal addons. From the same page you downloaded from...
Installation instructions:- Save TKing_Elfwood1.zip to your World of Warcraft folder, and extract. Allow it to overwrite files if prompted to do so, unless you suspect there are custom graphics belonging to an addon (in any case this shouldn’t be a problem).
(PLEASE NOTE) When you select Extract All, make sure the destination for the extraction is \program files\world of warcraft - and not \program files\world of warcraft\TKing_Elfwood1\ - simply backspace over the \TKing_Elfwood1 path.- The .zip file creates the folder \data\interface with additional subfolders containing the graphics (.blp) files. To remove this theme, simply remove the subfolders beneath \data\interface.
- Launch World of Warcraft.
If you have a question about one of the installation steps dont hesitate to ask.