Fatal error: Uncaught Error: Using $this when not in object context in /wp-content/plugins/nextgen-gallery/lib/ngg-db.php:245
Stack trace:
#0 /wp-content/plugins/nextgen-gallery/lib/sitemap.php(77): nggdb::get_gallery('8', 'pid', 'ASC', true, 1000)
#1 /wp-includes/shortcodes.php(357): nggSitemaps->add_gallery(Array, '', 'nggallery')
#2 [internal function]: do_shortcode_tag(Array)
#3 /wp-includes/shortcodes.php(235): preg_replace_callback('/\\[(\\[?)(nggall...', 'do_shortcode_ta...', 'Firma Alfa Wyk\xC5...')
#4 /wp-content/plugins/nextgen-gallery/lib/sitemap.php(54): do_shortcode('Firma Alfa Wyk\xC5...')
#5 /wp-includes/class-wp-hook.php(286): nggSitemaps->add_wpseo_xml_sitemap_images(Array, '970')
#6 /wp-includes/plugin.php(203): WP_Hook->apply_filters(Array, Array)
#7 /wp-content/plugins/wordpress-seo/inc/sitemaps/class-sitemap-image-parser.php(113): apply_filters('wpseo_sitemap_u...', Array, '970')
#8 /wp-content/plugins/wordpress-seo/inc/sitemaps/class-post-type-sitemap-provider.php(624): WPSEO_Sitemap_Image_Parser->ge in /wp-content/plugins/nextgen-gallery/lib/ngg-db.php on line 245