saving fast and furiously is probably the best advice, daz can be a perfectly well behaved beast and then it eats you in a fit of unprovoked madness especially when you get to trying to break the dforce engine.

if you're not already it might be a good idea to load items in and set up your initial scene with the preview window set to smooth shaded or texture shaded and only iray preview once everything is more or less placed as you want it. conflicting content can also cause instant crashes on attempting to load a figure (I somehow made a g8f morph that would kill my saved scene and daz on load).

the log file can get pretty long winded if you've been running for a while so you can try delete it then launch and load your scene that way there will be only the current info in the log file and it might be easier to diagnose.