Some people have a problem where Adsense search returns no results, this can sometimes happen when you chose specific sites to search, rather then choosing the "entire web" option.
Brugbart first encountered this problem doing last redesign of the site, since Google changed the search code, the solution was quite simple. So where you enter the sites that you want to be searched, you need to use the asterisk (*) wildcard on subdirectories of your site.
Using the asterisk at the end of a directory, will allow all subdirectories and URLs to be searched. Typically people would do something like below, only to find that it doesn't work.
Google would just remove the last dash, which may or may not have something to do with it. But in any case, adding the asterisk at the end solves the problem.
How to make it work
The below syntax will work, remember that sites and URLs are separated by line-breaks, and doesn't need the "http://" part..
To make it search the entire sites, simply do like below.