What a fine mystery. This is a LabVIEW Forum, and your question is about mini-Refprop, described as "a free sample version of the full REFPROP program (located at www.nist.gov/srd/refprop) and is meant for use as a teaching tool in the introduction of thermodynamics to students". It also says "The executable for Version 10 of mini-Refprop was set to expire on Dec. 31, 2019." There's a "fix", but it involves downloading and installing the full REFPROP routine, which you can't run (because you don't have a license for it), but apparently contains updated (and working) pieces of the code that mini-Refprop requires.
Do you see the word "LabVIEW" in that description? The only hint is when you ran the mini-Refprop program after its license expired, you got a message saying you needed to install NI DataSocket 19.0.
So it looks like Refprop was developed by NIST programmers who use LabVIEW. As it happens, I know someone at NIST who programs in LabVIEW (we go to the same LabVIEW Users Group occasional meetings and have had lunch together several times a year to talk LabVIEW).
Assuming my assumptions are correct, you may have a "partial" installation of mini-Refprop that is missing part of the Run Time Engine for LabVIEW 2019. If your school has an academic LabVIEW license, see if you can find a LabVIEW guru on campus (ask in the School of Engineering, perhaps). If you can find a computer running LabVIEW 2019, you can try to install mini-Refprop and see if that fixes the problem.
Bob Schor
