Valve's new distribution system, SteamPipe, has thrown a wrench in the works for many games, tools, and mods working with Steam. This includes HLDJ. After letting the dust settle a bit after the first few updates, and Valve moving the first few games over to the new system, it's become clearer what the changes bring:

• a new filesystem structure (VPK)
  
• a new way of specifying search paths

HLDJ will continue to function as normal, although you need to re-add your games or find where they've been moved to. Pending a few updates, and once the new system is stabilized, HLDJ will try to take advantage of the new features in pipe.