make sure u have ur trainer .exe in the right folder. assuming u have the retail copy then u'll have two folders: Origin and Origin Games. the trainer .exe should be inside: Origin Games/Syndicate/System/Win32_x86_Release <- this is the folder in which ur trainer .exe should be.
@Pwiz: i'm pretty sure the game hasn't been patched yet and if u have the trainer in the right folder it really works perfectly. u really don't need to take a second look at it.