Solution 1:
Make sure your F-LOCK and NUMLOCK keys are on.
Solution 2:
Try running the trainer first (right click "Run as Administrator") then running the game. Once the game is up and running, ALT+TAB out to the trainer and press F1 to activate. Then ALT+TAB back to the game and use the options.
Solution 3:
Temporarily disable/uninstall all antivirus, firewall and other security software. This type of issue can be caused by interference of third party software, typically security software. Some security products will still block or interfere with trainers even when disabled. Some must be completely uninstalled or the trainer and its temporary files whitelisted. Consult your security product documentation for instruction on how to do this.
Solution 4:
Make sure you fully extract the trainer from the .rar, .zip or .zipx archive before trying to run it. When running it, please right click on the trainer .exe file and choose "Run as Administrator". It may also be necessary to do this on the game as well. Trainers need full Windows permission to access the game in memory and create temporary files. It may also be necessary to give full permissions to the Windows TEMP folder.