I see you are continuing to struggle with some of the basic fundamentals of LabVIEW. You can click on the the run arrow or go to Window>Show Error List to get the reason the VI is broken. You have connected Pulse Duration to the bottom of the divide function. I think you wanted it connected to the top. Then, you made period an output indicator instead of a control. If you haven't done it already, you should really take some time out to take an on-line tutorial.
