MBX1000 HotSync Monolight

Fatal error: Uncaught Error: Call to undefined function hex_darker() in /home/alexmu6/priolite.us/wp-content/themes/pptitan/lib/shortcode.lib.php:169 Stack trace: #0 /home/alexmu6/priolite.us/wp-includes/shortcodes.php(393): button_func(Array, 'BUY NOW', 'button') #1 [internal function]: do_shortcode_tag(Array) #2 /home/alexmu6/priolite.us/wp-includes/shortcodes.php(265): preg_replace_callback('/\\[(\\[?)(dropca...', 'do_shortcode_ta...', '<p style="text-...') #3 /home/alexmu6/priolite.us/wp-includes/class-wp-hook.php(308): do_shortcode('<p style="text-...') #4 /home/alexmu6/priolite.us/wp-includes/plugin.php(205): WP_Hook->apply_filters('<p style="text-...', Array) #5 /home/alexmu6/priolite.us/wp-includes/post-template.php(255): apply_filters('the_content', '<p style="text-...') #6 /home/alexmu6/priolite.us/wp-content/themes/pptitan/page.php(147): the_content() #7 /home/alexmu6/priolite.us/wp-includes/template-loader.php(106): include('/home/alexmu6/p...') #8 /home/alexmu6/priolite.us/wp-blog-header.php(19): require_once in /home/alexmu6/priolite.us/wp-content/themes/pptitan/lib/shortcode.lib.php on line 169