Well the theme you mentioned isn’t what you get if you click download. The actual theme Kelontong is a Premium Theme. You can find it here:
http://tokokoo.com/portfolio/kelontong/
If you are using Kelontong that you found as a free download, it’s probably a “Ripped” version. If this is the case, you probably have more problems than the error you speak of. You should download the plug-in used by the WP Theme Review Team called ThemeCheck. It will display errors, and malicious code (base64, gzdeflate, etc…).
Good Luck.