Pete, Ivan, Lars, Dariusz; after having found a forgotten call to JAVA11 in config.sys LIBPATH, and now deleted it (every previous C:\JAVA11 call found in config.sys now replaced by C:\APPS\OpenJDK), LVMGUI.CMD object has then began to work as clicked.
So I could place a shadow copy where I like to find that, and call it Logical Volume Manager, ready to use.
Thank you for assisting me to understand how to fix this issue