This would be a bug with CCleaner v2.10 and with Firefox 3.0 when you view sites some times urls are not found now with urls that are not found some times they go over here on top click History, then - Show All History, now you have a box that pops open that says Library now at the bottom you will see something that says Unsorted Bookmarks now them sites that get placed in there they do not get cleaned as you will see them urls in your drop down Address Bar all the time witch is annoying they just build up and you just keep seeing them with all other sites you go to
Those are your Unsorted Bookmarks, they are created when you bookmark a site and select the folder option "Unsorted Bookmarks". CCleaner will never clean or touch your bookmarks intentionally.
See here for more info.
mushu13 i was not talking about the bookmark part i was talking about Unsorted Bookmarks witch was add it on FireFox 3.0 witch was not add it to clean that part on CCleaner yet witch brokein urls just get placed in there and it shows all the time in your drop down Address Bar witch is annoying to have them there when there broken urls anyways