The only time I ever tried to roll back a patch resulted in having to reinstall Vue (can't remember if that was V5i or V6i though).  I was thinking of just calling updates that roll back fixes as undates.

On the memory size stuff,  I've had 1.3GB bryce5 files that have opened up to the full 2GB of ram usage (32bit XP) fine and then happily render - bryce5 doesn't need much ram to render in, though I've never had anything above a 5000x5000 texture come through intact in anything. Vue definitely doesn't like large amounts of image based textures as far as I can tell - my most problematic scenes have that (mainly due to poser imports) as their common feature.

Dreams are just nightmares on prozac...
Digital WasteLanD