OK, I watched the video. You need to correct a couple things. First, your mechanics grip (aka Dealer's Grip) is all over the place. It is your biggest problem at this point. Fix it before you do another trick! Get the packet settled into a good mechanics grip with the left index finger on the outer edge and the other left fingers along the right edge of the packet. The thumb should be resting comfortably on the packet. Stop and enjoy the beauty of the mechanics grip. Drink it in. This doesn't need to be a death grip, just a stable and comfortable grip before you start the count.
Second problem. You are pivoting the top card incorrectly. In fact, you're not really pivoting the card. I would say that you are "sliding it out of the way" which is bad technique...and sliding it way too far. For the Dealers Grip-style Elmsley Count you need to pivot the top card up just enough to get a clean grip with your right thumb, index and middle finger. With your left thumb pivot the top card about 1 cm upward and to the left. At this point, the three cards underneath should still be aligned as a three card packet. If not, go back to step 1 and practice the grip and pivot before you go any further.
Third issue. You are grabbing the packet too low. When you pivot, it exposes the outer, right corner of the three card packet. Take that exposed corner.
Fourth issue. You're manhandling the cards. A good Elmsley Count can be executed slowly and the spectator will see nothing. Slow it way down for now. Speed will come as you get better. It should be a casual display of the cards not a karate chop of each card.
Watch this routine I created that does a bunch of Elmsley Counts. Notice the pivot and where I grip the underlying packet.http://www.youtube.com/watch?v=FYYnaIALQCM
Fix the mechanical issues and the practice this count for a couple months and it will be smooth as butter. Hope that helps!