wp crashes after plugin upgrade to 3.1

After I upgraded the Editor and Menu Access plugin to 3.1 my web site crashes with the following log message:

[Sun May 30 15:05:06.231973 2021] [php7:error] [pid 22874] [client 63.117.14.9:43782] PHP Fatal error: Uncaught Error: Call to a member function add_cap() on null in /nas/content/live/gmcastaging/wp-content/plugins/editor-menu-and-widget-access/admin/caps.php:37\nStack trace:\n#0 /nas/content/live/gmcastaging/wp-includes/class-wp-hook.php(292): emwa_set_capabilities('')\n#1 /nas/content/live/gmcastaging/wp-includes/class-wp-hook.php(316): WP_Hook->apply_filters(NULL, Array)\n#2 /nas/content/live/gmcastaging/wp-includes/plugin.php(484): WP_Hook->do_action(Array)\n#3 /nas/content/live/gmcastaging/wp-settings.php(560): do_action('init')\n#4 /nas/content/live/gmcastaging/wp-config.php(120): require_once('/nas/content/li...')\n#5 /nas/content/live/gmcastaging/wp-load.php(37): require_once('/nas/content/li...')\n#6 /nas/content/live/gmcastaging/wp-blog-header.php(13): require_once('/nas/content/li...')\n#7 /nas/content/live/gmcastaging/index.php(17): require('/nas/content/li...')\n#8 {main}\n thrown in /nas/content/live/gmcastaging/wp-content/plugins/editor-menu-and-widget-access/admin/caps.php on line 37