Failed to get cursor position: Access is denied.

Every so often, the error "Failed to get cursor position: Access is denied." crops up from our game built on Unity 3. We never had this on Unity 2.61 on our other game, but it's extremely sporadic even on Unity 3. It seems to happen only when players are alt-tabbing out of the game, or otherwise don't have the game in focus.

Bug report from our users.

Any idea what causes this? Is this a bug in Unity, or what?

If it didn't happened before, on 2.61, it probably is a bug.