Hi Maddy :)
If i understood, you are speaking about the box with the title ForenEinträge in your index page?
(this is the only box where it looks like a query is in progress, sorry i can not understand german).
If you are speaking about this, as i saw there is nothing in your forum. Andrey will tell you more, but i thing that your problem will be fixed, if you go to the admin of orca (admin-->plugins-->orca forum--> manage your forum. Just create forum and group.
And, i thing, rss see more will start working after there is something in your forum, else you will have the message there is no post or something like this (i can not remember exactly who is this message in english).
I hope i help...