I checked the logs and it wasn't reported as false error this year. I marked it now and it works. So you must be doing something wrong.
When you click False error New tab should appear with text
ErrID = 511 UserID1 = 6712015 UserID2 = 0 IP=xx.xx.xx.xx False error succesfully recorded. It will be removed on next monday.
At this point it is stored in database. Do you get this text?