black screen when broadcast

Previously I used os 10.9 and apple remote desktop 3.8.3 and had no problems broadcasting to student computers. Since I've upgraded to OS 10.10 and ARD 3.8.4, I'm having trouble broadcasting. Usually I have to try 4 or 5 times before I can broadcast. The first few times there will just be a black screen on student computers, and on the 4th or 5th attempt, it will broadcast. Also, sometimes the ARD program will freeze up and I have to force quit and then restart. Any help would be greatly appreciated!