Your basic problem is that the program calls two different VIs that return different data types. One, TSI4000SerialRead returns an array. The other, CME60AFlowmeterReading returns a scalar. The program has them connected to the same place and that is not allowed. I suspect that the fix is to modify TSI4000SerialRead to return just a scalar but without the instrument or a lot more details on it, I wouldn't know what would be required. The program itself is one that I would normally use as an example in how NOT to program LabVIEW. All of the nested sequence structures and local variables make the program very difficult to understand, debug, and maintain. I wish you luck.
p.s.
Please stop shouting your questions - that's what all caps means;)