I’ve figured out how to get it to work but it requires this process every time SGP is started.
When starting SGP, dismiss the boxes asking for registration info. SGP will finally open after a couple of times. Under the help menu choose ‘Manage Licences’ and delete your machine in the window that comes up. Then, go back to SGP and choose 'Register this Machine" and now enter your info. It should then say it was successful. You can then use SGP 3.x as usual but do not close it or the process has to be repeated.