Error message with WP Defender

Hi,

in Admin-Backend this error is displayed:

"Notice: fwrite(): send of 91 bytes failed with errno=1 Operation not permitted in /home/staff/websites/hilfe.macbay.de/neu/wp-content/plugins/wp-defender/app/module/audit-log-module/controller/class-wd-audit-logging-controller.php on line 57
"

What does it mean and how can I get rid of it?

Thank you and kind regards,
Sascha