Because it's the only option at my disposal right now, I've blocked all new topics and replies. Obviously this is not a permanent solution, but the situation is not one I have the power/authority to fix.
Hopefully things will be reopened soon. Thank you for those who brought things to my attention quickly.
Ok -- was able to get in touch with the webmaster, and he has suspended registrations, so I'm reallowing the posting. Please don't whistle any more of the posts in question -- I'll delete them, but it's a manual process.