error with defeneder software

defender was installed and had been running for a periode but today it gives this error if i try to logon to wp admin "Fatal error: Call to undefined function get_core_checksums() in /data/home/madboden/public_html/wp-content/plugins/wp-defender/app/module/scan-module/component/class-wd-scan-api.php on line 205". I have uninstalled defender on madbodenhh,dk