1 MARCH 2013
Update: the link has been fixed.
If you too are getting that asinine "12 minutes" message when you click the link to make your deposit, call Travel Planners at 877-552-6642. They will take your credit card number over the phone and make the deposit.
I tried that link from multiple browsers, laptops, IP addresses and 2 phones, and got stonewalled every time. I know I'm not the only one, and Travel Planners answered my initial email with an automated "you'll hear from us within 3 days" - when of course, the deposit needs to be made in 3 days.
The Travel Planners woman didn't sound surprised at all about the link, but nor did she mention any plans to fix the issue. So don't count on it getting rectified before the cut-off period if you're having trouble - just call and lock down your room to be safe.
The upside of this irritation - she let me upgrade my room slightly for a mere fourteen dollars.