Custom Taxonomies Cababilities

Hi @curtismchale:

Try 'river-class' instead of 'Class', i.e.:

 register_taxonomy( 'river-class', array( 'fvww-river-guide' ), array(
    'hierarchical'              => true, //operates like a category
    'labels'                    => $labels,
    'rewrite'                   => true,
    'public'                    => true,
    'show_ui'                   => true,
    )
); // ends class taxonomy

Actually what caused you to stumble was your choice of a capitalized taxonomy name (i.e. “Class” vs. “class”) although I’d really recommend against such a generic name as “class” to avoid potential conflict which is why I suggested “river-class” instead.