I would have posted in the mentioned thread, but it seems to be locked.
You provide a link in this thread Link to a working version of the witcher trainer.
When I download the trainer (version 1.5 retail) I only get the text-file but not the trainer. If I download the trainer from this place Link I get the both the trainer and the text-file. Unfortunately it doesn't state for which version this trainer is (Steam or Retail?). I have the GOG-Enhanced Version.
I also bought the latest GOG version of the enhanced edition of the game and I am encountering the exact same problem.
When I try to download the latest retail version of the 1.5 trainer (THE WITCHER MEGA TRAINER 1.5 RET (ENH. ED.)) I get a zip file containing only the text file. If I try to download the latest steam version of the trainer (THE WITCHER MEGA TRAINER 1.5 STM (ENH. ED.)), the trainer does not work when I press F1 at the main menu.