Hi Sherry,
I would concentrate on the VISA question. There are certain core files within LabVIEW that do not change with each new version release. These files are contained within the VI.LIB library. When attempting to save your main VI in a format compatible with a previous version of LabVIEW, your current version of LabVIEW recognizes that the copy of these VIs would be identical to the copy that is with the older version of LabVIEW. Therefore, in the interest of time and disk space, it does not save the older version. However, the reference for that VI is still there. Therefore, when you open your new VI in the old version of LabVIEW, it calls the older SubVI just as it would in the newer version. Thus, your top-level VI should function perfe
ctly in the older version of LabVIEW.
Consider checking out NI-SPY to determine what could be causing the failure. NI-SPY can give you a detailed log of everything that is happening at the driver level.
Hope this helps out!
Best Regards,
Aaron K.
Application Engineer
National Instruments