How come? Is it because you can't download them in tf2? well if you try downloading it somewhere that not loading screen of tf2, it will think it came from another server. It happend last time I tried this.
map downloads many times work, but for anyone else, before trying that, see if you can find that map in your tf/downloads/maps/ folder. If you see the map and it's got a small file size, delete it. The map file is corrupted and now it won't redownload since it believes you already have the map.
But sure, if you just can't download it due to a proxy of some sort or something else, use gamebanana.