Eh, you can disable DHT if you like, it makes little difference unless you\'re trying to download \"trackerless\" torrents.
Technically speaking, DHT makes every client basically its own tracker, in a sense. (For instance, if a regular tracker goes down or if there isn\'t one at all, you can still keep downloading the files.
TorrentSpy has a great page on
trackerless torrents if you want to know more.
To disable it in Azureus, goto Tools -> Options and select Connection. Under the Peer Sources table, uncheck everything except \"From a tracker\". This should resolve those pesky messages from popping up.