I am supposed to defend the miners, but there is only neutral brotherhood around.

Flying away to restart this step doesn't help.

It seems that the quest got bugged for some reason, sometimes those thing happen in "other than english" versions, and you have Deutsch version.

Please, send us your save file and log.txt to that mail I mentioned. oliver@starpointgemini.com
Also just copy paste this problem you described here to e-mail.

Sorry for the inconvinience. :-/