some problems

Hey,
I installed this but I have following problems:
images doesn't display on non-root pages.
So if I go to url:
url.com/forums/main-forum/
the images all change into
url.com/forums/main-forum/images/...

So I get all broken images.

Second is that the urls get changed when I'm on the page, but not in the links themselfes.
Like when i'm on my index i get:
forums/forumdisplay.php?f=2
And when i click on that, i go to:
forums/main-forum/

But why isn't it changed in the link??

thx in advance,
seba