Warning: Attempt to read property "fields" on null in /var/www/wp-content/plugins/calculatorpro-calculators/calculatorPro.php on line 239

Fatal error: Uncaught Error: Attempt to assign property "fields" on null in /var/www/wp-content/plugins/calculatorpro-calculators/calculatorPro.php:239 Stack trace: #0 /var/www/wp-includes/shortcodes.php(395): CP_widget_shortcode(Array, '', 'calc') #1 [internal function]: do_shortcode_tag(Array) #2 /var/www/wp-includes/shortcodes.php(235): preg_replace_callback('/\\[(\\[?)(calc)(...', 'do_shortcode_ta...', '[calc id=3697]') #3 /var/www/wp-content/plugins/cornerstone/includes/shortcodes/raw-content.php(18): do_shortcode('[calc id=3697]') #4 /var/www/wp-includes/shortcodes.php(395): x_shortcode_raw_content('', '[calc id=3697]', 'x_raw_content') #5 [internal function]: do_shortcode_tag(Array) #6 /var/www/wp-includes/shortcodes.php(235): preg_replace_callback('/\\[(\\[?)(calc|x...', 'do_shortcode_ta...', '<div id="cs-con...') #7 /var/www/wp-content/plugins/cornerstone/includes/_classes/classic/class-shortcode-preserver.php(134): do_shortcode('<div id="cs-con...') #8 /var/www/wp-includes/class-wp-hook.php(310): Cornerstone_Shortcode_Preserver->restore_shortcodes('<div id="cs-con...') #9 /var/www/wp-includes/plugin.php(205): WP_Hook->apply_filters('<div id="cs-con...', Array) #10 /var/www/wp-includes/post-template.php(256): apply_filters('the_content', '[cs_content][cs...') #11 /var/www/wp-content/themes/x/framework/views/global/_content-the-content.php(17): the_content() #12 /var/www/wp-content/themes/x/framework/legacy/functions/frontend/view-routing.php(36): include('/var/www/wp-con...') #13 /var/www/wp-content/themes/x/framework/legacy/functions/frontend/view-routing.php(85): x_render_view('/var/www/wp-con...', Array, true) #14 /var/www/wp-content/themes/x/framework/views/renew/template-blank-4.php(18): x_get_view('global', '_content', 'the-content') #15 /var/www/wp-content/themes/x/framework/legacy/functions/frontend/view-routing.php(36): include('/var/www/wp-con...') #16 /var/www/wp-content/themes/x/framework/legacy/functions/frontend/view-routing.php(85): x_render_view('/var/www/wp-con...', Array, true) #17 /var/www/wp-content/themes/x/framework/legacy/templates/template-blank-4.php(15): x_get_view('renew', 'template', 'blank-4') #18 /var/www/wp-includes/template-loader.php(106): include('/var/www/wp-con...') #19 /var/www/wp-blog-header.php(19): require_once('/var/www/wp-inc...') #20 /var/www/index.php(17): require('/var/www/wp-blo...') #21 {main} thrown in /var/www/wp-content/plugins/calculatorpro-calculators/calculatorPro.php on line 239