Yeah, the trainer seems to have a few minor issues. Infinite Health works, but you can still die. I tanked an endurance mission for 20+ missions, but then a Shinobi randomly killed me out of the blue. Otherwise it seems to work well. I also can't get the Ducats cheat working. The trainer just says error. All other options work.
Try a manual cleaning of any old data.
Delete trainer and all files in
C:\Users\USERNAMEHERE\AppData\Local\Temp
C:\Users\USERNAMEHERE\Cheathappens\Work
C:\Users\USERNAMEHERE\AppData\Roaming\Cheat Happens\0x90
Reboot PC to clear excess memory, get a fresh copy of latest trainer and
make sure trainer in is folder excluded from virus scans.
C:\Users\USERNAMEHERE\Cheathappens
may need to be added to exclusions as well. Run trainer as admin and try again.