Well, just to prove you wrong, I did a test: I've deleted my game, set it to run at afterbirth and downloaded it again. Then, to prevent corruption, I moved my savegames somewhere else. Finally, I downloaded the latest afterbirth trainer - the one which says PATCH 01.25.2016 - and ran the game, ran the trainer and tried to activate it. you know what, it WORKED. And here's a video as proof.
The video is currently uploading though, it will take an hour or two to be uploaded.
If you did it exactly as I did and it still didn't work(if not try it like I did), it's a problem on your computer, NOT the trainer.
Edit: Mobile internet's upload speed turned out to be much faster. Uploading using mobile(tethered to PC). A few minutes left for upload to finish, then it will start processing.
Edit 2: Video is up.
[Edited by TheSingular, 7/18/2017 7:23:13 AM]
Well, good for you and i was just saying. Glad it worked