Firstly as others are suggesting, only troubleshooting for you is; either just try once including the class file temporarily hardcoded or to echo/print the values of each element of the array $value['folder'], $value['class'], $value['method'] including ROOT:
echo ROOT . $value['folder'] . '/' . $value['class'] . '.class.php';
Does this really shows the correct value? If yes there should (must) not be the problem if you are in the PHP version of having Dynamic use of Class Names. Otherwise there is nothing to explore in your code and don't have to pull out your hair. As per my knowledge, you are on the right track. Better you let us know the PHP version that you are in and at least try to test what the guys have suggested here.
Furthermore, I would recommend you to use require() instead of include() since require() produce FATAL error and halts the script while include will continue with an E_WARNING and maybe you have set error_reporting something to hide warnings. So try once this as well:
error_reporting(E_ALL | E_STRICT);
require ROOT . $value['folder'] . '/' . $value['class'] . '.class.php';
Secondly I would recommend you to use Autoloading Classes in PHP which you can find here http://php.net/manual/en/language.oop5.autoload.php with some examples. If you go for it, you don't have to worry about if it is included or not it will automatically include when you create an instance of a class:
$Plugin = new $value['class'];