Well, my lobby server is working fine, but when I click "join game" the screen just goes black, without going to the game. The situation just gets worse when I ctrl+alt+delete, so I have to shove a pencil into the "override" button, or watever it is on laptops. This has happened several times.

Is it something wrong with the server, am I just missing something very simple, or what?

Hmm, well there are some things you can do
1) Did you install DirectX properly?
2) Restart your computer
3) Try reinstalling Soldat.
4) Or you might have things running in the backround

Hope i helped.