Hello Olav!
Bealieve me you are participating in a hidden network called Altnet it lays on top of Kazaa but you never see's it unless you pay for Brilliant Networks service.You can read all about it on these sites.Articles:
Article 1 Article 2 Article 3
Read more about Brilliant Digital and their network Altnet:
http://www.brilliantdigital.com/ http://www.altnet.com/
But fortunatelly there is a way to get rid of the scumware go here and download the software you need to get rid of it:
B3D Killer