While it was a general statement, I'm the one who coded phpVMS 5.5.2 to work in php 7.0-7.2 -- hence the version phpVMS 5.5.2.72
5.5.2.72 doesn't fully work/install on php versions above 7.2
There will be errors and incompatibilities.
My guess is it was either installed under php 7.2 and then the php version was changed to 7.4 or possibly error reporting is off or not set up to show pertinent errors - or both.