Quote: "Is it not because the sky background's black, and is being rendered transparent?"
Nope. Otherwise it would do that on all machines wouldn't it? So far it seems to work fine on every NVidia based machine I've tried. Of the 5 computers in the house that can run DBPro based apps, only my laptop has ATI graphics.
Looking up the specs on the FireGL 3100, I would say the issue is a lack of video memory. DBPro wants at least 128MB, but DC probably requires a fair amount more to run properly.
While this isn't a bug, it's sad that Simul doesn't really seem to care about the bugs that have existed for quite a while. Even when it does work, moon artifacts pop up and disappear at random, and a few of the commands simply crash the app. (sigh...)