I registered with coolboard.com and also with ezboard.com - I'm more impressed with ezboard.com than with coolboard.com - the only problem is trying to set moderators on ezboard.com but I don't have to worry about that for a while because the site isn't quite ready yet.
Alright, I will probably get shunned by all webmasters for doing this, but Coolboard offers something very similar to the Ultimate Bulletin Board. http://www.coolboard.com
I am not sure of how many levels you can have, but I believe it is very similar to this and it is free. So, I hope this helps.
There is also the option of getting a remotely-hosted CGI bin. There are sites that offer CGI-bin space on their servers and you just use them so that you can host your site on your server and have your CGI stuff on their servers.
To set permissions, you need Cute FTP or telnet access. I recommend Cute FTP. Go to http://www.TuCows.com to download the trial version. Registration is $30US, I think. Once you have uploaded the files, right click on them in the remote directory. About half-way down that menu, you'll see 'CHMOD' which is what you use to change permissions.
I am currently using coolboard on http://www.StreetBikersUnited.com . Man is it hard to get people to post. I'm workingon a site about golfing in Hawaii, and plan on using UltraBoard.
I just created a website called goodlucktoday.com. One feature, I included in was a forum. I first started with Ultra board, EZboard, and several free scripts, none worked(maybe I was too dump for setting up PERL script). Finally, I gave up and called dcscript.com to have them set up their DC forum scripts in my website which cost 100 plus something. Now, it is up and running. The only problem maybe that I don't know how to transfer it to some place else and may have to pay them again in the future. So may be somone who successfully installed any free script would kindly write a detailed installation instruction for dummy would be great.