I want to learn kiwijs through it's documentation but there are errors on website

In Getting Started Section:-
Fatal error: Uncaught Error: Call to a member function id() on array in /home/gamefroo/public_html/kiwijs.org/wp-content/plugins/crayon-syntax-highlighter/crayon_formatter.class.php:36 Stack trace: #0 /home/gamefroo/public_html/kiwijs.org/wp-content/plugins/crayon-syntax-highlighter/crayon_formatter.class.php(538): CrayonFormatter::format_code('', Array, Object(CrayonHighlighter)) #1 [internal function]: CrayonFormatter::delim_to_internal(Array) #2 /home/gamefroo/public_html/kiwijs.org/wp-content/plugins/crayon-syntax-highlighter/crayon_formatter.class.php(516): preg_replace_callback('#()#msi', 'CrayonFormatter...', 'bower install k...') #3 /home/gamefroo/public_html/kiwijs.org/wp-content/plugins/crayon-syntax-highlighter/crayon_highlighter.class.php(166): CrayonFormatter::format_mixed_code('bower install k...', Object(CrayonLang), Object(CrayonHighlighter)) #4 /home/gamefroo/public_html/kiwijs.org/wp-content/plugins/crayon-syntax-highlighter/crayon_highlighter.class.php(186): CrayonHighlighter->process() #5 /home/gamefro in /home/gamefroo/public_html/kiwijs.org/wp-content/plugins/crayon-syntax-highlighter/crayon_formatter.class.php on line 36

In General Tutorials Section:-

Warning: sizeof(): Parameter must be an array or an object that implements Countable in /home/gamefroo/public_html/kiwijs.org/wp-content/plugins/wordpress-firewall-2/wordpress-firewall-2.php on line 300

Warning: preg_replace(): Compilation failed: invalid range in character class at offset 4 in /home/gamefroo/public_html/kiwijs.org/wp-content/plugins/crayon-syntax-highlighter/crayon_langs.class.php on line 340

Warning: Cannot modify header information - headers already sent by (output started at /home/gamefroo/public_html/kiwijs.org/wp-content/plugins/wordpress-firewall-2/wordpress-firewall-2.php:300) in /home/gamefroo/public_html/kiwijs.org/wp-includes/pluggable.php on line 1281