OK, I confess that I didn't open your attached files earlier. I looked at the included DLL, which does, actually, contain LabVIEW code. The Serial Test says "This Virtual Instrument program was written using National Instruments LabVIEW 4.0.1 for Windows 95". Hmmm. This may, in fact, be "the latest drivers", who knows?
I will say, however, that it uses functions I've never seen, but which seem to be in the LabVIEW Library. The one that is probably throwing the Error is a function called Serial Port Write, a function buried in vi.lib\Instr\serial.llb. Unlike the VISA functions, this function does not have an Error Wire associated with it, attesting to its ancient roots.
I'm going to assume that the VariSpec device follows VISA and Serial protocals. My recommendation is that you find a LabVIEW Developer in your area who can come and develop for you a simple package that will completely replace the two-decade-old and very obsolete VariSpec routines with much simpler and more robust VISA code that can reside right in the code you are developing to run this Instrument, without needing any DLLs (you may also want to reconsider the structure and use of the .INI file).
You can (and should) also test your device using MAX. When you plug your device into a Serial Port (are you using COM1? are you using a DB9-style plug? are you plugging into a USB port? and, if so, do you have a USB-to-Serial adapter/converter?), you should be able to "see" it in MAX, configure it (Baud Rate, Termination Character, etc.) and communicate with it (send it a command, read its response, as per the Manual). If you can do this, it will be very simple for a knowledgable LabVIEW Developer to give you a modern, working set of routines to "do what you want to do" with this Instrument.
Bob Schor
