Just guessing here: Do you know the LabVIEW version of the VIs?
Can you open the examples that ship with LabVIEW 5.1?
(LabVIEW 5.1 is ancient history (~1998) and cannot open VIs created with newer version of LabVIEW, e.g. 6, 6.1, 7, or 7.1. Time to upgrade!)
🙂