Trial ver. will not accept Certificate

If you are using Zone Alarm on your computer then see here.

Otherwise you should contact GPSoftware for assistance as it's unlikely any of the users here at the forum will know how to help. (This isn't a known issue AFAIK, except the Zone Alarm-related problems.) You should be able to use your evaluation details on the Support page I've linked. Be sure to use the same email address that you used to get your evaluation certificate.