Reading back A Bom I can see that you are still using 8.03 access version. If you are starting to experience slow downs etc on your forums, its perhaps because either your server or your database is struggling to keep up
You could do a few things
1. Clear out old posts
2. Lock topics down so only registered users can access them
3. Seriously consider moving to Web Wiz and upgrading to the latest software and technology which should pretty much get your problems sorted

It just depends on how you feel, but older versions of the software are indeed "buggy" and open to problems from outside sources too. Have a chat with Bruce and see what he suggests. Depending on what you have (ie how many sites, etc) it may be a good time to make a change
I hope that helps, but you can always PM me for further information