I am trying to remember what I was doing at the time of my crashes and if I remember right everything was fine with importing various poser models until I loaded some RNDA conifer trees. Then I could render fine and move around in the scene all right but it would crash on saving everytime. I just had to reload a previous saved version without the trees to get the scene back. Dont know if that was what caused it or just some random weird corruption. Have to play around more i guess.