The current pre-release of the client ("pioneer" in the version) is only compatible to itself. So you can only play with other testers. Please be aware!
I've created new account and moved my files there. Everything works swell and dandy now, I think. I haven't actually played it yet but I'm able to log in and actually see the launcher.
Thanks for your help mister, it has been greatly appreciated as I can now play the game.