Help with forum virus posters?

hi, i am on this millsberry forum. it was all peaceful then these computer controlled virus posters starting joining. the administrator is never on is there is only one moderator. these accounts are multiplying by the day and as we speak it is getting worse... could someone plz tell me any kind of solution yo get these virus posters off the site. just remember the one moderator doesn't have the power to kick these people off the site, the admin is never on and theres no way of contacting these robotic virus posters. so could someone plz tell me a way to help keep these virus posters away or at least stop joining. (i am only a member)