Histogram VI is broken because one of the Build Array functions is missing a connection to an input. It was hard to see in the original VI because of overlapping nodes withing the block diagram. I did a BD cleanup so that things are more visible.
Black Box VI has an odd construct. There is a Feedback Node surrounding a shift register on a while loop that is set to run once. That is redundant. You can safely remove the feedback node, or remove the while loop. The VI should function the same. (Verify the operation because the feedback nodes can have different initialization conditions that can make them behave differently from a shift register.)