It might be possible, that the MOD/trainer was not meant to support the pirated/cracked COPY of this game, since it has been coded to work only on the LEGIT STEAM version ?
But, @STiNGERR can only help you further with this issue. Btw, have you tried other obvious possible workarounds ?
When you run the Infinity app/tool, make sure to run it as an ADMIN/Administrator, and temporarily disable any Antivirus/AV, as well as firewall on your PC.
You can also add “Infinity” as an exception/exclusion, if using any AV, but better turn it off, for the time being.
First launch the game from your folder location, and then open the Infinity tool. If this doesn’t work, first launch the Infinity tool, and then start the game through this MOD, by clicking on the START button.
Try both these methods. There might also be an Architecture Mismatch as well.
Also, give the ‘Best practices’ section a read, under this TOPIC: