Sorry I am not a super Linux expert myself, so not sure how to get past the error you have with X11. In openSuse I just have to add the devel packages for things like bison, libpng etc using the package manager to resolve dependencies after that its fairly straightforward.
Unless you're really attached to ClarkConnect I would still recommend openSuse, its very easy in open suse to do all those things you mentioned (file sharing, web server, mail etc) as benefits of ClarkConnect. I think thats just an oddball distro and their marketing makes you think its easier, but openSuse is very friendly. That web interface you mention is probably WebMin, their site seems to be down at the moment but heres the wikipedia page for it. You can install WebMin on openSuse if you like it, but you might find the built in admin features even easier.
Hope it helps,