How can I get rid of these popups that appear everytime I start surfing?

http://ads.inetfast.com/RealMedia/ads/adstream_nx.ads/advertising720oct03.cm/@Frame1?x
This is the address from which in Hypertext protocolls make popup screens appear every time I start surfing on the web. Even by just using my startingpage Google.nl (I'm in Holland you see..) these invitations for gambling at GoldenPalace.com come about. So does anybody out there have the cure for this please?

Greetz