Shea Bunge on "[Plugin: Code Snippets] Snippet code disappeared"

Assuming the faulty snippet in question is the one displayed in the screenshot and on GitHub, you can try using this code:

function aweber_single_post() {
	if ( is_single() ) {
		echo '<script type="text/javascript" src="http://forms.aweber.com/form/57/1350500557"></script>';
	}
}

add_action( 'woo_post_after', 'aweber_single_post' );