one user creating vb database errors
 

hi i have got a weird issue *there is a banned user on my site who keeps trying to login / create posts i think he is using some script * all the times he is on mys ite i keep getting vb database errors * unless i kick him out of server with my firewall :( and always he return with new ip * i banned nearly 80 ips till now * any effective way to stop him ?