Your forum has been showing insane amounts of "guests" online I have noticed. The 8000+ guests are all shown as refreshing the (Unoffical Xsyon Community Ventrilo) page even though there hasn't been an update there in 5+ days.
Just thought I would point this out so you can get a fix.
I would also like to add I personally believe your cookie timer for user timeout is far too long for a forum. Thirty minutes is a long time for a user to go inactive and I believe it skews your statistics.
Thanks and best of luck.