I guess these don't exist, or there are none that are free?
The one that I have a license too will spike my processor and it's only a one-computer license. I can't use it on my server because of that and I need something that I can have others download onto their own computers.
OK I was bored, so I downloaded this software and installed\configured it in about 20 mins. Looks pretty good, I run my forum from my own server so have access to the log files.
IMHO for what it's worth, I would say give it a try, the only thing it will cost you is some time.