Looks like there are some incompatibility issues with NOD32 (4.0.x) and Dropbox: http://forums.dropbox.com/topic.php?id=18656 Fortunately the 4.2.x release looks to have fixed it. Anyone experience similar issues?
Running this combination on 2 computers of mine with NOD32, never experienced issue's as mentioned in that topic. Only experienced such issue once, on a notebook running MSE, but that was with a smaller file.