Adblock Plus

I'm having problems with the following web page
http://ad.doubleclick.net/ddm/clk/28109 ... G_ALWAYSON

When I go on certain sites I get the above page and can't progress further. how do I stop it launching.

The actual site name is ad.doubleclick.net

it was the British Airways site I was trying to access.

thanks

-if you want to upload a screenshot use imgur.com then post here the link
-anyway could be your system is infested by some malware / adware
see http://malwaretips.com/blogs/remove-mac-os-x-virus/