Hi, I have the same problem when I first started also.
Press the reset button that is on the Arduino board first then upload your program(Upload to I/O Board button), you should do this right after you press the reset button. If that doesn't work try pressing the program button first(Upload to I/O Board) then wait a few second, like 1 or 2 second, then press the reset button on the board.
Or you can go to this link and follow step 6 if the above methods does not work. http://www.arduino.cc/en/Guide/Windows