At the risk of belaboring the obvious, are you entering your resort confirmation number and other information where it asks for it on the restaurant reservation page? If you're staying on site, that's the only way to
"unlock" the calendar for the 90+10. If you're doing this and still can't get to your 90+10, it's undoubtedly a system glitch, as many have encountered this. If you can't make it work, you'd be better off to call.