wtf, my forum is gone and I get this:

Warning: require_once(bad-behavior/bad-behavior-generic.php) [function.require-once]: failed to open stream: No such file or directory in [path]/global.php(28) : eval()'d code on line 10

Fatal error: require_once() [function.require]: Failed opening required 'bad-behavior/bad-behavior-generic.php' (include_path='.:/usr/lib/php:/usr/local/lib/php') in /home/xsquid/public_html/forum/global.php(28) : eval()'d code on line 10

I can't even get in my admin panel, is this a joke??????

I get viewing directory contents not permitted on the forum and the above trying to get into the admincp, how can i get rid of this?

I know that a lot of high traffic PHP sites use this. It's been used on Wordpress for quite some time and I've had it running on several of my own, which is why I implemented this for my board. My own board gets about 5000 hits a day but that's not a big board per se. I can tell you that it doesn't slow down my board but does seem to reduce load.
It is not a joke. I used the same product file to install my own instance and I have never had this problem.

Is it possible that you have a CHMOD problem for a folder or files? I honestly don't know what is causing your problem because I have never experienced it.

I disabled the plugins through config.php to get into the admoncp and uninstall it, board is back up. It's remaining unstalled, not touching it again.

Did you upload the directory contents in the zip file into your forum root? The zip file unzips into a bad-behaviour folder and you should upload that into your forum root.

The "no such file" seems pretty obvious that it cannot even find the file. Do you have a bad-behaviour-generic.php file within a bad-behaviour folder on your forum root?

How does this relate to vb and caching/ x-cache?

After installation, do we need to edit any settings?

There are no "settings" for this. This is the generic implementation of Bad-Behaviour. You may want to ask the script developer more about how his script works. My assumption on the above is that the script protects activity that is occuring within PHP activity and cached content is often put into html files that the script would not be able to detect.

Does this script protect against download tools like httrack? That would save a lot of bandwidth.

I recommend you direct such questions to the script developer. The only thing I have done is provide a way for your board to call the functions that the script provides. It worked for me and the script has been very successful at blocking spam attempts on Wordpress sites that I run. I make no claims to having the exhaustive understanding of what the script does or does not do nor what the script developer has in mind for the future of the script.

I simply provided a way to implement the generic mode of the script as the script developer describes on his site.