There’s not much I can really do as I can’t see what the issue is from my end. The theme package itself isn’t broken as this has never happened before on any of my sites, nor have any other users experienced this. This leads me to believe there is something else wrong with your setup.
The only thing I can do is recommend that you double check and make sure that you have Genesis installed properly. If it is installed, reinstall it, and also reinstall the Optimal theme. This issue usually happens when you try to install a child theme (Optimal) without the Parent theme installed (Genesis)…..especially when the error says – “Broken theme, template missing”