Running the following code on Windows Vista (I know, I know), PHP 5.3.9, the ReflectionClass constructor actually throws a ReflectionException when the desired class cannot be instantiated:

<?php
    try {
        $ReflectedClass = new ReflectionClass('NonExist');
    } catch (LogicException $Exception) {
        die('Not gonna make it in here...');
    } catch (ReflectionException $Exception) {
        die('Your class does not exist!');
    }
?>