Since the "down time " yesterday for most of us im getting 2 problems

New members trying to make new accounts get this error
Unable to execute queryTable './bizhat_s2/multiforums_log

AND GUESTS can Now post and i never changed options there just able to post ?

my forum is getting spammed with sex sites pics and dodgey links how can this get stopped without adding ADMIN authorisation? It was ok before as i said.