Hi
yes there were two issues, one was the card used as you do need the fasted card you can get and I use 90/mb sec Lexar pro, anything slower and the card cannot keep up. The second (and this was the major issue) was the firmware update, this sorted it out totally and not had an issue since. This update was the first update after the release of the camera and not sure what that was, but if you navigate to the Nikon website and make sure you download the latest one this will be fine.
I hope this helps as it bugged the hell out of me.