Thanks for the great plugin!
I've discovered a problem with the AJAX functions on the Crayon Admin page when updating from Crayon 1.12 to 1.13.
The sample code display and the list of posts show "Incorrect arguments for 'wp-load' when using XAMPP. Unix-type environments work OK.
The issue seems to be the crayon_is_path_url test added to crayon_die_if_not_php in global.php.
On Unix-type systems a relative path to the file within the server's file system is expected, and is generated OK into the [wp-load] item in the CrayonSyntaxSettings array.
On Windows, however, the path is absolute, not relative and starts with the drive letter. This means function crayon_is_path_url now returns true as the path contains a scheme, (in my case "C" as XAMPP is installed on my C: drive).
As a workaround I commented out the reference to crayon_is_path_url.