If it was the retail one or anything below trainer #2 it is only good for Win 7 and below. If it was either of the top 2 then Double Check A/V settings.
Is the anti-virus that is tied to you browser severed as well? May need to add www.cheathappens.com to whitelist so the trainer authenticates. Also would not hurt to add the trainer to exclusions in the anti-virus as depending on which one it is, it may never be truly off. C:\Users\USERNAMEHERE\Cheathappens\Work should be excluded as well. Some A/V, the only way to make sure it is off is to completely remove it or go to their support site and find out how to disable it.