Hello @Britgirl and all,
I’ve got exactly the same problem (some error messages about missing entry points for this function or that) during installation. Although I’m on x64 Windows 10. Yes, I did use Firefox to download the installation .exe (nomachine_8.2.3_4_x64.exe). But, to be honest, your reply (that Firefox is the culprit) sounds dubious. I just re-downloaded the .exe with Google Chrome, and the downloaded file is exactly the same as what Firefox downloaded (I compared with fc /b) .
So no, it does not look like Firefox has anything to do with this. 8.2.2.4_x64.exe is broken, please fix it or at least give a link to an older (“stable”) version.