Hidden Cookies

Hello,
When I use "Karen's Cookie Viewer" The search feature brings up several cookies that I have chosen to leave. This is as it should be. No problem here.
But!!!
When I go to "Firefox 11 (Beta4)_Tools_Options_Privacy_remove individual cookies"
It will list 258 cookies that are stored on my computer.

Cookies such as "adavisor.net" with a name of "id"
Another cookie such as "ad.wsod.com" wotj a name of "i_1"

I did a search of all my drives and cannot find any trace of these cookies.
What can anyone tell me about this problem?
Any advise on how to solve it.?
Owen