Random image block only appears on the first page

Hi, I installed the random image block on my server, and I am using the dev version, since the normal versions did not work at all. I made a directory files/banners in which I put a lot of pictures. When I go to the front page, it shows the picture properly, the picture shows is on http://site/files/banners/1.jpg for example. If I go to any other page, the block shows no picture at all, if I view the source code it shows that the picture points to

http://site/node/files/banners/1.jpg
which should be
http://site/files/banners/1.jpg.

This error only occures in any other page but the frontpage. So somehow it inserts "node" in the picture url.