always right click on the trainer and run it as administrator.
make sure the trainer you are using corresponds to you game version number. If the game version number is higher than the latest trainer version number, you will need to wait until an updated trainer is released.
security software can interfere with the execution of the trainer. you may need to disable/uninstall all anti-virus, firewalls and other security software and/or add the trainer or the folder that the trainer is in to the exceptions list on your security software.
IE 10 can cause problems with many trainers, if you have IE 10, uninstall it for troubleshooting purposes. More information on uninstalling IE 10 can be found here Link