I haven't encountered this bug before. If you could give some information on what happened beforehand, it could be useful. Does it happen every time?
It's also possible that you should wait a little. The game should be rendering the map when you first load it, so if your system is low-end, it might take some time.
It's not that bad, and it would probably take something much worse for the game to actually lag enough that it would freeze for even a minute at this point. It's not that demanding, normally it doesn't take enough time to even notice. Are you saying that it happens even if you start the new game? If so, then I really can only assume some kind of hardware incompatibility, but that is strange.
If you don't mind, could you give me your GPU model? Maybe I'll be able to find something out.
