After read your post, I sniff on the data transmitted between your server and my PC a bit. What I find that forum "forums.equipped.org" is using the Apache server. Though most likely I can fingerprint the underlay OS from here, but to avoid causing any alarm on the hosting company's IDS as a hacker, I use the information provided by "netcraft.com": The server OS is Linux.
Apparently the forum is using UBB BBS software. According to
http://www.ubbcentral.com the basic requirement are PHP 4.3+ and MySQL 4 or 5 ,these two software packages are standard components provided by most hosting companies these days, especially those offer Linux server hosting.