Did you at least get the "invalid code" message? I did a dry run a little bit before, and I kept getting "Sorry, that code is not valid" when I entered it on the page that showed "Bummer!"

I also started seriously hammering 3 minutes before time, in case my clock was slow. My tickets state I got them at exactly 10:30 by EventBrite's server, but my PC clock said 10:28.