I went to download the 2013 css setti release, and found the only working tracker to be dht, it still downloaded, but no other tracker worked. I know for a sad fact that publicbt and openbittorrent have turned off their trackers, so you may need to run your own tracker or find a new one. You don't want to rely only on DHT as DHT stands for "Distributed Hash Table" and it tends to get tracked by cops looking for piracy