How to create flexible WordPress Parent Themes

Notice: Undefined offset: 0 in /var/html/dev/wp/wp-content/plugins/crayon-syntax-highlighter/crayon_formatter.class.php on line 532Fatal error: Uncaught Error: Call to a member function id() on array in /var/html/dev/wp/wp-content/plugins/crayon-syntax-highlighter/crayon_formatter.class.php:36 Stack trace: #0 /var/html/dev/wp/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 /var/html/dev/wp/wp-content/plugins/crayon-syntax-highlighter/crayon_formatter.class.php(516): preg_replace_callback('#()#msi', 'CrayonFormatter...', 'require_once ( ...') #3 /var/html/dev/wp/wp-content/plugins/crayon-syntax-highlighter/crayon_highlighter.class.php(166): CrayonFormatter::format_mixed_code('require_once ( ...', Object(CrayonLang), Object(CrayonHighlighter)) #4 /var/html/dev/wp/wp-content/plugins/crayon-syntax-highlighter/crayon_highlighter.class.php(186): CrayonHighlighter->process() #5 /var/html/dev/wp/wp-content/plugins/crayon-syntax-highlighter/crayon_wp.class.php(703): CrayonHighlighter->output(true in /var/html/dev/wp/wp-content/plugins/crayon-syntax-highlighter/crayon_formatter.class.php on line 36