It doesn't look like you're calling add_action() correctly. It should be more like:

add_action( 'edit_page_form', 'wpse96952_editor' );
function wpse96952_editor() {
    wp_editor(
        "Sample",
        'mycontent',
        array( 'textarea_name' => 'mycontent' )
    );
}

It doesn't look like you're calling add_action() correctly. It should be more like:

add_action( 'edit_page_form', 'wpse96952_editor' );
function wpse96952_editor() {
    wp_editor(
        "Sample",
        'mycontent',
        array( 'textarea_name' => 'mycontent' )
    );
}

(content changed to mycontent after I read @vancoder's comment)