Is your downloads folder a OneDrive/GoogleDrive or something like that? That's my first guess for your issue running the installer directly from your downloads folder. I just downloaded that same version, and ran install for both client and server (from my downloads folder, Win10 Home), and it worked flawlessly.
Which version of Java are you using (java -version from the commandline should show it)?
For MC/Forge 1.17, I used the latest Java 16 from AdoptOpenJDK.
Please keep this forum in English.
Some zip managers like to take control of the .jar file extension away from Java.
Make sure you have Java installed and try running Jarfix once, then try the installer again.