flomol79 on "polylang and Yoast SEO conflict"

Hello,

I have installed Polylang for the first time in its last version 1.6 and I got this fatal error message:
Fatal error: Call to a member function get_languages_list() on a non-object in /home/ultimate/www/wp-content/plugins/polylang/include/plugins-compat.php on line 114

It seems to be a conflict with the plugin Yoast WP SEO because 1)The message disappear when I deactivate WP SEO and 2) line 114 is refering to:

* WordPress SEO by Yoast
	 * reloads options once the language has been defined to enable translations
	 * useful only when the language is set from content
	 *
	 * @since 1.2
	 */
	public function wpseo_translate_options() {
		<strong>if (defined('WPSEO_VERSION') && !PLL_ADMIN && did_action('wp_loaded'))</strong> {
			global $wpseo_front;
			$options = version_compare(WPSEO_VERSION, '1.5', '<') ? get_wpseo_options_arr() : WPSEO_Options::get_option_names();
			foreach ( $options as $opt )
				$wpseo_front->options = array_merge( $wpseo_front->options, (array) get_option( $opt ) );
		}
	}

Any idea how to fix it?? Thanks

(non static front page)

https://wordpress.org/plugins/polylang/