Agree with jc. A few questions; will the scene itself save? Or is it just the render you're having problems saving? I see from the world browser you're grouping stuff; try hiding layers as well. And when was the last time you defragged? I've had problems rendering to disk with a real fragmented drive. If you have XP or W2K Pro, you can get into the diagnostics, like Dr Watson, for your crash logs. Those are invaluable to send to E-on for tech support help.

Sgiathalaich