i got your problem i am also having the same problem i also don't know the reason i am also looking for some solution to this
You need to turn your language and targeted areas filter off. This is what I did to do that: Click on Get Links. Then click on Additional Search Options. In the options select Link Type: Banners. Relationship Status: My Advertisers. Language: All. Advertiser's Targeted Area: All. After that click on the Find button. It will bring the list of your advertisers. Then if you click Home and go to your advertisers on the bottom of the home page, all your banners and links should be searchable now.