Here's my problem: I want a room in a cellar to be darker than the rest, so I created a roommarker around it and changed its lighting template to something darker. It is now darker in the room, however stuff outside of the room does not get rendered while I am inside of this room, only the lights. If I am outside of the room and look inside, I also only see the lights, only when I enter it it shows the rest.
Pictures:
Looking into the room with the marker: http://www.abload.de/img/screenshot28vzaw.jpg
Moving 3 steps forward, so I am in the room: http://www.abload.de/img/screenshot316a5v.jpg
Looking back to where I came from, the outside of the room I am in now: http://www.abload.de/img/screenshot44hafa.jpg

So, why is this happening? I also tried putting the rest into another room, however I still had these rendering problems.

Have you followed this tutorial regarding room markers/bounds? http://www.creationkit.com/Bethesda_Tutorial_Optimization If you have just the one box, anything outside the box will not get rendered. If you add a second box to the un-rendered area, you will need a portal between the 2 to tell the engine what to render.

Oh, I forgot the portal.. thanks for the help.