DHT is "Distributed Hash Table". It's used for trackerless torrents.

Azureus recently (well, not THAT recently, like 4 or 5 months ago) rolled distributed tracking into the main azureus client. That's what you're on there, with its crappy 2 peers apparently.

Distributed tracking is a good idea for things that you'd worry about ... like distributing documents detailing a despot's despotism in the country you live in, or downloading the latest hollywood release while avoiding a horribly short-lived single tracker. However, it's not very good for the anime community, and I'd highly recommend disabling it.

It looks like the first torrent in question is, in fact, running on the distributed tracker. The info hash is different than the hash that gotwoot's tracking for the same thing, so gotwoot tracker doesn't know what the hell that file is, and is thus rejecting it. I'd strongly urge you to disable distributed tracking in preferences, and to re-download the torrent and attempt to resume it from the tracker that's actually tracking it.