yes, it's only one single server (virtual one with a few little "hello world" sites by other people as far as I know)...
3 years ago we've planed this relaunch and our hoster as well as all information sources told us it won't be a problem to login with 1 click to all domains... however, after we've ordered the 15 additional domains to (ccj39.de, ccj39.com, world-of-civ.de, world-of-civ.com) and installed all the things 2.5 year ago, we've noticed that it won't be possible to login automatically to all domains... for this reason we've started to try different methods to bypass the problem... however up2day no way was really working... we've also thought about subdomains, but this also won't fix the login-problem, because the core of this site needs one login per subdomain too and we've also a lot of parts in sourcecode using the domainname to decide what to show and so on...
if you've any good idea how we can solve the problem, let me know

... the only way to solve it seems to be to use subdirs instead of subdomains, but therefor a lot of changes in sourcecode are needed and we need to forward all old links to the right new ones, which will need a lot of time (and I need to learn some things for this first ^^ )