error on plugin

this error is showing in our server logs for the sites with this plugin installed:

An error of type E_ERROR was caused in line 267 of the file /public_html/wp-content/plugins/mainwp-child-reports/connectors/installer.php. Error message: Uncaught Error: Call to a member function get() on null in /public_html/wp-content/plugins/mainwp-child-reports/connectors/installer.php:267
Stack trace:
/public_html/wp-content/plugins/mainwp-child-reports/includes/connector.php(31): MainWP_WP_Stream_Connector_Installer::callback_upgrader_process_complete(Object(Theme_Upgrader), Array)
/public_html/wp-includes/class-wp-hook.php(286): MainWP_WP_Stream_Connector::callback(Object(Theme_Upgrader), Array)
/public_html/wp-includes/class-wp-hook.php(310): WP_Hook->apply_filters(”, Array)
/public_html/wp-includes/plugin.php(465): WP_Hook->do_action(Array)
/public_html/wp-admin/includes/class-wp-upgrader.php(835): do_action(‘upgrader_proces…’, Object(Theme_Upgrader), Array)
/public_html/wp-admin/includes/class-theme-upgrader.php(299): WP_Upgrader->run(Array)
/home/inmyownq/public_html/wp-admin/update.php(189): Theme_Upgrader->upgrade(‘genesis’)in/update.php(189): Theme_Upgrader->upgrade(‘genesis’)

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