Composer install problem

[fafayqa]

I am trying to install this php library using Composer FOR THE FIRST TIME EVER but whatever I try it always give an error: Unable to launch a new process.

I am using kind of "manual install trick" shown HERE as I do not have option running custom install scripts on a live server, I can only manually upload files.

So I did exactly step-by-step what was required, yet I did not move a bit as it immediately throws at me abovementioned error in a big red square in CMD window as soon as I run CMD command php composer.phar update (as required).

I am on Win10 x64 using USBWebserver with PHP 8.1 and have all the file access privilegues.